Advances in Interventional Cardiology
1990; Elsevier BV; Volume: 65; Issue: 4 Linguagem: Inglês
10.1016/s0025-6196(12)60956-2
ISSN1942-5546
AutoresDavid R. Holmes, Ronald E. Vlietstra, Steven J. Reiter, Dennis R. Bresnahan,
Tópico(s)Cardiovascular Function and Risk Factors
ResumoThe field of interventional cardiology is growing widely. This growth is the result of improvements in existing technology, development of new technology, and expansion of criteria for the selection of patients. Percutaneous transluminal coronary angioplasty (PTCA) remains the mainstay and is used to treat an increasing number of patients with coronary artery disease that manifests as stable or unstable angina or acute myocardial infarction. Atherectomy is being used to “debulk” lesions and remove atheromatous plaque as well as to remove intimal flaps after PTCA. The insertion of an intracoronary stent is a strategy designed to treat intimal dissections and acute closure as well as to attempt to decrease the incidence of restenosis. Finally, intracoronary laser therapy—independently or in combination with PTCA—is being evaluated as a treatment approach for more diffuse disease, acute occlusion, and prevention of restenosis. The field of interventional cardiology is growing widely. This growth is the result of improvements in existing technology, development of new technology, and expansion of criteria for the selection of patients. Percutaneous transluminal coronary angioplasty (PTCA) remains the mainstay and is used to treat an increasing number of patients with coronary artery disease that manifests as stable or unstable angina or acute myocardial infarction. Atherectomy is being used to “debulk” lesions and remove atheromatous plaque as well as to remove intimal flaps after PTCA. The insertion of an intracoronary stent is a strategy designed to treat intimal dissections and acute closure as well as to attempt to decrease the incidence of restenosis. Finally, intracoronary laser therapy—independently or in combination with PTCA—is being evaluated as a treatment approach for more diffuse disease, acute occlusion, and prevention of restenosis. The year 1977 ushered in a new era in the treatment of patients with cardiovascular disease—interventional cardiology.1Grüntzig AR Senning Å Siegenthaler WE Nonoperative dilatation of coronary-artery stenosis: percutaneous transluminal coronary angioplasty.N Engl J Med. 1979; 301: 61-68Crossref PubMed Scopus (1877) Google Scholar With the introduction of percutaneous transluminal coronary angioplasty (PTCA) in that year, the mindset that the ostia of the coronary arteries were inviolate was broken. Since then, an explosive growth in technology has facilitated the development and testing of additional procedures such as coronary atherectomy, arterial stents, and intra-arterial laser therapy. This growth is expected to continue and should provide an expanding number of treatment options in addition to conventional medical and surgical therapy. PTCA was initially reserved for patients with single-vessel disease who had a single, concentric subtotal stenosis, well-preserved left ventricular function, and stable but medically refractory angina.1Grüntzig AR Senning Å Siegenthaler WE Nonoperative dilatation of coronary-artery stenosis: percutaneous transluminal coronary angioplasty.N Engl J Med. 1979; 301: 61-68Crossref PubMed Scopus (1877) Google Scholar, 2Holmes Jr, DR Vlietstra RE Balloon angioplasty in acute and chronic coronary artery disease.JAMA. 1989; 261: 2109-2115Crossref PubMed Scopus (22) Google Scholar, 3Detre K Holubkov R Kelsey S Cowley M Kent K Williams D Myler R Faxon D Holmes Jr, D Bourassa M Block P Gosselin A Bentivoglio L Leatherman L Dorros G King III, S Galichia J Al-Bassam M Leon M Robertson T Passamani E co-investigators of the National Heart, Lung, and Blood Institute's Percutaneous Transluminal Coronary Angioplasty Registry Percutaneous transluminal coronary angioplasty in 1985-1986 and 1977-1981: the National Heart, Lung, and Blood Institute Registry.N Engl J Med. 1988; 318: 265-270Crossref PubMed Scopus (645) Google Scholar, 4Kent KM Bentivoglio LG Block PC Bourassa MG Cowley MJ Dorros G Detre KM Gosselin AJ Gruentzig AR Kelsey SF Mock MB Mullin SM Passamani ER Myler RK Simpson J Stertzer SH Van Raden MJ Williams DO Long-term efficacy of percutaneous transluminal coronary angioplasty (PTCA): report from the National Heart, Lung, and Blood Institute PTCA Registry.Am J Cardiol. 1984; 53: 27C-31CAbstract Full Text PDF PubMed Scopus (125) Google Scholar Although these patients still remain ideal candidates for PTCA, they account for only a minority of those who currently undergo dilation. An estimated 150,000 dilations were performed in 1986, and rapid growth continues. This exponential growth is the result of changing criteria for selection of patients, improved technology that facilitates dilation of more severe and complex coronary artery disease, and the number of patients who have restenosis and require repeat dilation.2Holmes Jr, DR Vlietstra RE Balloon angioplasty in acute and chronic coronary artery disease.JAMA. 1989; 261: 2109-2115Crossref PubMed Scopus (22) Google Scholar, 5Vlietstra RE Holmes Jr, DR PTCA in acute ischemic syndromes.Curr Probl Cardiol. 1987; 12: 703-762PubMed Google Scholar, 6Vlietstra RE Holmes Jr, DR PTCA: Percutaneous Transluminal Coronary Angioplasty. FA Davis Company, Philadelphia1987Google Scholar, 7Holmes Jr, DR Vlietstra RE Interventional Cardiology. FA Davis Company, Philadelphia1989Google Scholar Achieving optimal results with dilation is dependent on four factors: (1) adequate catheterization facilities, (2) up-to-date angioplasty equipment, (3) appropriate selection of patients, and (4) operator experience. Each of these four factors is important in achieving the desired result. The catheterization laboratory has become increasingly specialized.7Holmes Jr, DR Vlietstra RE Interventional Cardiology. FA Davis Company, Philadelphia1989Google Scholar, 8Holmes Jr, DR Wondrow MA Julsrud PR Radiographic techniques used in cardiac catheterization.in: Pepine CJ Hill JA Lambert CR Diagnostic and Therapeutic Cardiac Catheterization. Williams & Wilkins, Baltimore1989: 113-127Google Scholar, 9Holmes Jr, DR Bove AA Wondrow MA Gray JE Video x-ray progressive scanning: new technique for decreasing x-ray exposure without decreasing image quality during cardiac catheterization.Mayo Clin Proc. 1986; 61: 321-326Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar, 10Wondrow MA Bove AA Holmes Jr, DR Gray JE Julsrud PR Technical consideration for a new x-ray video progressive scanning system for cardiac catheterization.Cathet Cardiovasc Diagn. 1988; 14: 126-134Crossref PubMed Scopus (11) Google Scholar For interventional procedures, the requirements for optimal imaging have become more stringent. The imaging equipment must obtain and display high-quality images to allow visualization of multiple views of the coronary arteries before, during, and after dilation. Without the capability of high-quality stop-action video recording, dilation should not be performed. Radiation exposure to patients, physicians, and technical staff has become an increasingly important concern.11Holmes Jr, DR Wondrow MA Gray JE Vetter RJ Fellows JL Julsrud PR Effect of pulsed progressive fluoroscopy on reduction of radiation dose in the cardiac catheterization laboratory.J Am Coll Cardiol. 1990; 15: 159-162Abstract Full Text PDF PubMed Scopus (71) Google Scholar, 12Dash H Leaman DM Operator radiation exposure during percutaneous transluminal coronary angioplasty.J Am Coll Cardiol. 1984; 4: 725-728Abstract Full Text PDF PubMed Scopus (43) Google Scholar, 13Cascade PN Peterson LE Wajszczuk WJ Mantel J Radiation exposure to patients undergoing percutaneous transluminal coronary angioplasty.Am J Cardiol. 1987; 59: 996-997Abstract Full Text PDF PubMed Scopus (54) Google Scholar During dilation, fluoroscopy times are increased; this increase is proportional to the number of vessels being dilated. As more multivessel dilation procedures are performed, this problem will be magnified. Careful shielding of the equipment and radiation aprons for physicians and technical personnel can limit exposure. Recently, new digital imaging techniques have shown considerable promise in actually reducing radiation exposure in addition to improving the quality of the images.9Holmes Jr, DR Bove AA Wondrow MA Gray JE Video x-ray progressive scanning: new technique for decreasing x-ray exposure without decreasing image quality during cardiac catheterization.Mayo Clin Proc. 1986; 61: 321-326Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar, 10Wondrow MA Bove AA Holmes Jr, DR Gray JE Julsrud PR Technical consideration for a new x-ray video progressive scanning system for cardiac catheterization.Cathet Cardiovasc Diagn. 1988; 14: 126-134Crossref PubMed Scopus (11) Google Scholar Major changes in the technology of balloon dilation equipment have occurred since its introduction in 1977.4Kent KM Bentivoglio LG Block PC Bourassa MG Cowley MJ Dorros G Detre KM Gosselin AJ Gruentzig AR Kelsey SF Mock MB Mullin SM Passamani ER Myler RK Simpson J Stertzer SH Van Raden MJ Williams DO Long-term efficacy of percutaneous transluminal coronary angioplasty (PTCA): report from the National Heart, Lung, and Blood Institute PTCA Registry.Am J Cardiol. 1984; 53: 27C-31CAbstract Full Text PDF PubMed Scopus (125) Google Scholar, 6Vlietstra RE Holmes Jr, DR PTCA: Percutaneous Transluminal Coronary Angioplasty. FA Davis Company, Philadelphia1987Google Scholar, 7Holmes Jr, DR Vlietstra RE Interventional Cardiology. FA Davis Company, Philadelphia1989Google Scholar, 14Holmes Jr, DR Cohen HA Vlietstra RE Optimizing the results of balloon coronary angioplasty of nonideal lesions.Prog Cardiovasc Dis. 1989; 32: 149-170Abstract Full Text PDF PubMed Scopus (10) Google Scholar, 15Werns SW Topol EG Review of hardware for PTCA.J Intervent Cardiol. 1988; 1: 209-219Crossref Scopus (10) Google Scholar, 16Van Tassel RA Gobel FL Rydell MA Vlodaver Z MacCarter DJ A less traumatic catheter for coronary arteriography.Cathet Cardiovasc Diagn. 1985; 11: 187-199Crossref PubMed Scopus (10) Google Scholar, 17Finci L Meier B Roy P Steffenino G Rutishauser W Clinical experience with the monorail balloon catheter for coronary angioplasty.Cathet Cardiovasc Diagn. 1988; 14: 206-212Crossref PubMed Scopus (18) Google Scholar, 18Thomas ES Williams DO Neiderman AL Douglas JS King III, SP Efficacy of a new angioplasty catheter for severely narrowed coronary lesions.J Am Coll Cardiol. 1988; 12: 694-702Abstract Full Text PDF PubMed Scopus (24) Google Scholar, 19O'Keefe Jr, JH Holmes Jr, DR Reeder GS Bresnahan DR A new approach for dilation of bifurcation stenoses: the dual Probe technique.Mayo Clin Proc. 1989; 64: 277-281Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar These changes, which make the initial equipment seem crude, inflexible, and cumbersome, have facilitated the expanded use of dilation and the improvement in success rates from approximately 60% in 1977 to 90% in 1988. Technologic advances continue; during 1988, approximately 20 new catheter systems were introduced. Knowledge of the advantages and disadvantages of these systems is essential for optimizing dilation. In some circumstances, a variety of dilation catheters will be equally effective; in other circumstances, the specific characteristics of a single dilating catheter may be necessary for a successful dilation procedure. Dilation systems consist of three components: a guiding catheter needed for intubation of the ostium of the vessel to be dilated; the balloon dilating catheter itself; and a guide wire that is removable, movable, or fixed to traverse the stenosis. A large variety of currently available guiding catheters facilitate dilation from either a brachial or a femoral approach. The initial catheters used were 9 F in diameter to accommodate the large dilating catheters. Since then, smaller guiding catheters, usually 8 F but even 7 F in some instances, have become widely used. Even though these catheters have become smaller in external diameter, the internal diameter has increased in size, a feature that allows excellent opacification of the coronary artery with test injections during dilation. Some of these catheters have a deformable soft tip,16Van Tassel RA Gobel FL Rydell MA Vlodaver Z MacCarter DJ A less traumatic catheter for coronary arteriography.Cathet Cardiovasc Diagn. 1985; 11: 187-199Crossref PubMed Scopus (10) Google Scholar which is intended to help decrease trauma to the coronary ostia during dilation. The available dilating catheters have changed substantially. The sizes range from 1.5 to 4.0 mm for coronary arterial and vein graft dilations. Changes in the design of these catheters have provided a lower profile so that they can more easily pass through stenoses, better “trackability” so that they can be used in tortuous vessels, and also some stiffness of the catheter shaft so that the catheter can be “pushed” across the stenoses. At the same time, the balloon material has become stronger. Made of polyvinyl chloride or polyethylene, these balloons can routinely deliver 10 to 12 atmospheres or now even up to 20 atmospheres. Although most of these balloons maintain a constant diameter over a wide range of pressures, some will expand slightly (approximately 10%) above 8 atmospheres. The specific balloon dilation catheter chosen depends on the preference of the physician, the size of the artery to be dilated, its location within the coronary arterial tree, and the severity of the stenosis. The third essential component of dilation systems is the guide wire. The earliest systems had a fixed guide wire at the tip of the dilating catheter which lacked directional control. This construction limited the ability to negotiate through the coronary arterial system to reach the stenosis. A major design modification was the subsequent introduction of a movable guide wire that could be shaped, independently directionally controlled, and removed. Guide wires are now available in sizes from 0.36 to 0.46 mm and with varied flexibility and stiffness. Even smaller wires (0.25 or 0.30 mm) are planned for the future. Most guide wire systems allow extension and exchange capability so that the wire can be placed across the stenosis and a variety of dilating catheters can be used, if needed, for dilation. Some of these movable guide wire systems have been modified so that the guide wire can be advanced within the coronary artery but not totally withdrawn from it through the balloon catheter. This design allows excellent trackability within the coronary artery but prevents the use of a long exchange wire. A recent catheter design has returned to a fixed guide wire system.18Thomas ES Williams DO Neiderman AL Douglas JS King III, SP Efficacy of a new angioplasty catheter for severely narrowed coronary lesions.J Am Coll Cardiol. 1988; 12: 694-702Abstract Full Text PDF PubMed Scopus (24) Google Scholar, 19O'Keefe Jr, JH Holmes Jr, DR Reeder GS Bresnahan DR A new approach for dilation of bifurcation stenoses: the dual Probe technique.Mayo Clin Proc. 1989; 64: 277-281Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar This system is essentially a balloon on a thin guide wire and has the advantage of the lowest profile; thus, the ability to cross very severe stenoses is improved. Although not as “steerable” as movable core systems, these new devices still are extremely helpful. Selection of the balloon and guide wire combination depends also on the preference of the physician and the detailed anatomy of the patient. For competent performance of PTCA, appropriate training and sufficient ongoing experience are needed.20ACC/AHA Task Force Report Guidelines for percutaneous transluminal coronary angioplasty: a report of the American College of Cardiology/American Heart Association Task Force on assessment of diagnostic and therapeutic cardiovascular procedures (subcommittee on percutaneous transluminal coronary angioplasty).J Am Coll Cardiol. 1988; 12: 529-545Abstract Full Text PDF PubMed Scopus (553) Google Scholar Not all angiographers should expect to perform angioplasty; difficult multivessel cases should be directed to the most experienced practitioners. A percutaneous femoral arterial approach is most commonly used for PTCA although catheters for a brachial cutdown method are available. Usually, an 8-F sheath is placed in the femoral artery after local infiltration with lidocaine. This sheath allows easy access during and immediately after the procedure. Both long (23-cm) and short (10-cm) sheaths are available. If the iliac vessels are severely tortuous, the long sheath may facilitate guiding manipulation of the catheter. After successful dilation, the sheath is sutured in place and left for a variable period. This sheath allows easy arterial access after PTCA if a complication occurs that demands urgent angiography. The time that the sheath is left in place depends on local practice and details of the outcome of dilation. If, for example, after PTCA a major dissection or a large amount of thrombus is present, the sheath may be left in for 24 hours and then repeat angiography can be performed. The most common practice is to leave the sheath in place from 6 to 24 hours and then remove it. In uncomplicated dilation cases, the 6-hour duration is more widely used. After removal of the sheath, local compression is used to obtain hemostasis. Subsequently, a period of 6 to 8 hours of bed rest is routine, after which ambulation is allowed. The patient can usually be dismissed from the hospital the day after removal of the sheath. If the sheath is removed the afternoon of dilation, the patient may be dismissed the next day. Before dilation, antiplatelet agents, including aspirin alone or aspirin in combination with dipyridamole, are given. This therapy has been shown to decrease the incidence of thromboembolic complications associated with dilation.21Schwartz L Bourassa MG Lespérance J Aldridge HE Kazim F Salvatori VA Henderson M Bonan R David PR Aspirin and dipyridamole in the prevention of restenosis after percutaneous transluminal coronary angioplasty.N Engl J Med. 1988; 318: 1714-1719Crossref PubMed Scopus (578) Google Scholar Heparin is usually administered as a bolus of 10,000 to 15,000 U after arterial entry and supplemented on the basis of activated clotting time measurements.22Ogilby JD Kopelman HA Klein LW Agarwal JB Adequate heparinization during PTCA: assessment using activated clotting time (abstract).J Am Coll Cardiol. 1988; 11: 237AAbstract Full Text PDF PubMed Scopus (109) Google Scholar If the sheath is to be left in more than 4 to 6 hours, a heparin infusion at 1,000 U/h is used. If the sheath is to be removed 4 to 6 hours after the end of the procedure, no additional heparin is given. Requirements for heparin vary depending on, among other factors, the size of the patient and the duration of the procedure. The activated clotting time has been found to be valuable in assessing the level of anticoagulant effect during the procedure and before removal of the sheath.22Ogilby JD Kopelman HA Klein LW Agarwal JB Adequate heparinization during PTCA: assessment using activated clotting time (abstract).J Am Coll Cardiol. 1988; 11: 237AAbstract Full Text PDF PubMed Scopus (109) Google Scholar If the procedure is lengthy, additional heparin should be given. Sublingually administered nitrates are usually given before dilation and may be continued for 24 hours to alleviate any coronary spasm. They may be supplemented with parenterally administered nitroglycerin if needed. Calcium channel antagonists are also given before PTCA and usually for approximately 2 weeks after the procedure. After the patient is dismissed from the hospital, aspirin is usually given long term, either alone or in combination with other antiplatelet agents. Patients with single-vessel disease still constitute a large percentage of those who undergo PTCA.2Holmes Jr, DR Vlietstra RE Balloon angioplasty in acute and chronic coronary artery disease.JAMA. 1989; 261: 2109-2115Crossref PubMed Scopus (22) Google Scholar The category of single-vessel disease, however, encompasses a large number of different patient subsets.14Holmes Jr, DR Cohen HA Vlietstra RE Optimizing the results of balloon coronary angioplasty of nonideal lesions.Prog Cardiovasc Dis. 1989; 32: 149-170Abstract Full Text PDF PubMed Scopus (10) Google Scholar Dilation is no longer confined to single, discrete subtotal proximal stenoses but is now used in patients with more diffuse or distal stenoses, lesions involving branch vessels, and chronic occlusions. In addition, PTCA is performed in patients with single-vessel disease who have acute ischemic syndromes—unstable angina, acute myocardial infarction, or postinfarction angina—as well as in patients with stable angina or patients without symptoms but with substantial ischemia.5Vlietstra RE Holmes Jr, DR PTCA in acute ischemic syndromes.Curr Probl Cardiol. 1987; 12: 703-762PubMed Google Scholar, 23Topol EJ Califf RM George BS Kereiakes DJ Abbottsmith CW Candela RJ Lee KL Pitt B Stack RS O'Neill WW Thrombolysis and Angioplasty in Myocardial Infarction Study Group A randomized trial of immediate versus delayed elective angioplasty after intravenous tissue plasminogen activator in acute myocardial infarction.N Engl J Med. 1987; 317: 581-588Crossref PubMed Scopus (754) Google Scholar, 24Simoons ML Arnold AER Betriu A de Bono DP Col J Dougherty FC von Essen R Lambertz H Lubsen J Meier B Michel PL Raynaud P Rutsch W Sanz GA Schmidt W Serruys PW Thery C Uebis R Vahanian A Van de Werf F Willems GM Wood D Verstraete M Thrombolysis with tissue plasminogen activator in acute myocardial infarction: no additional benefit from immediate percutaneous coronary angioplasty.Lancet. 1988; 1: 197-202Abstract PubMed Scopus (540) Google Scholar, 25De Feyter PJ Serruys PW van den Brand M Balakumaran K Mochtar B Soward AL Arnold AER Hugenholtz PG Emergency coronary angioplasty in refractory unstable angina.N Engl J Med. 1985; 313: 342-346Crossref PubMed Scopus (136) Google Scholar, 26TIMI Study Group Comparison of invasive and conservative strategies after treatment with intravenous tissue plasminogen activator in acute myocardial infarction: results of the Thrombolysis in Myocardial Infarction (TIMI) Phase II Trial.N Engl J Med. 1989; 320: 618-627Crossref PubMed Scopus (1052) Google Scholar, 27De Feyter PJ Suryapranata H Serruys PW Beatt K van Domburg R van den Brand M Tijssen JJ Azar AJ Hugenholtz PG Coronary angioplasty for unstable angina: immediate and late results in 200 consecutive patients with identification of risk factors for unfavorable early and late outcome.J Am Coll Cardiol. 1988; 12: 324-333Abstract Full Text PDF PubMed Scopus (132) Google Scholar Finally, PTCA is performed in patients with single-vessel disease who have a wide range of ventricular function, from normal left ventricular anatomy and function to considerably depressed left ventricular function. Currently, PTCA is used widely in various subsets of patients with single-vessel disease provided the lesion can be reached and dilated and provided the patient has provokable ischemia or a large amount of myocardium at risk—for example, disease of the proximal left anterior descending coronary artery. Many patients who undergo PTCA for single-vessel disease could be managed medically and have an excellent outcome. Application of dilation in these patients involves analysis of the safety and efficacy of the procedure, the patient's desires and expectations, and the potential for restenosis and its implications. Currently, many patients with provokable ischemia and a high-grade single arterial stenosis would prefer PTCA to medical or surgical therapy. A randomized trial of PTCA with medical therapy for single-vessel disease is currently under way (the Veterans Administration ACME [Angioplasty Compared to Medicine Evaluation] Study). The success rates of dilation in patients with single-vessel disease depend on the details of the coronary anatomy. In patients with a proximal, concentric subtotal stenosis, dilation should be successful in 95% of the cases (Fig. 1). In patients with less ideal anatomy, success rates are lower.28Ellis SG Roubin GS King III, SB Douglas Jr, JS Weintraub WS Thomas RG Cox WR Angiographic and clinical predictors of acute closure after native vessel coronary angioplasty.Circulation. 1988; 77: 372-379Crossref PubMed Scopus (604) Google Scholar, 29Sinclair IN McCabe CH Sipperly ME Bairn DS Predictors, therapeutic options and long-term outcome of abrupt reclosure.Am J Cardiol. 1988; 61: 61G-66GAbstract Full Text PDF PubMed Scopus (100) Google Scholar The lowest success rates occur in patients with chronic occlusions. In these patients, if the occlusion has been present for more than 3 months and is long, the chances of successful dilation are less than 50%.30Holmes Jr, DR Vlietstra RE Reeder GS Bresnahan JF Smith HC Bove AA Schaff HV Angioplasty in total coronary artery occlusion.J Am Coll Cardiol. 1984; 3: 845-849Abstract Full Text PDF PubMed Scopus (128) Google Scholar, 31Kereiakes DJ Selmon MR McAuley BJ McAuley DB Sheehan DJ Simpson JB Angioplasty in total coronary artery occlusion: experience in 76 consecutive patients.J Am Coll Cardiol. 1985; 6: 526-533Abstract Full Text PDF PubMed Scopus (143) Google Scholar, 32Melchior JP Meier B Urban P Finci L Steffenino G Noble J Rutishauser W Percutaneous transluminal coronary angioplasty for chronic total coronary arterial occlusion.Am J Cardiol. 1987; 59: 535-538Abstract Full Text PDF PubMed Scopus (152) Google Scholar Dilation may still be attempted if the patient has poorly controlled ischemia provided the patient and referring physician understand the reduced success rates. Most patients who undergo PTCA would be classified between these two extremes, and the success rates would vary accordingly. In these patients, one or more adverse angiographic factors are typically present. In this diverse patient group, unless there is a reasonable expectation of success (85% or more), our laboratory would not usually attempt dilation. The exception to this guideline in patients with chronic stable angina would be those with single-vessel disease, incapacitating symptoms, and severe ischemia, in whom surgical treatment is necessary. In these patients, even if the chance of successful dilation is less than 85%, dilation is often attempted to avoid or delay the need for a coronary artery bypass grafting procedure. In patients with single-vessel disease and acute ischemic syndromes, PTCA can be performed with success rates similar to those in patients with chronic stable angina.25De Feyter PJ Serruys PW van den Brand M Balakumaran K Mochtar B Soward AL Arnold AER Hugenholtz PG Emergency coronary angioplasty in refractory unstable angina.N Engl J Med. 1985; 313: 342-346Crossref PubMed Scopus (136) Google Scholar, 27De Feyter PJ Suryapranata H Serruys PW Beatt K van Domburg R van den Brand M Tijssen JJ Azar AJ Hugenholtz PG Coronary angioplasty for unstable angina: immediate and late results in 200 consecutive patients with identification of risk factors for unfavorable early and late outcome.J Am Coll Cardiol. 1988; 12: 324-333Abstract Full Text PDF PubMed Scopus (132) Google Scholar The hallmarks of the arterial pathologic changes in these patients are plaque Assuring and coronary thrombus (Fig. 2).33Ambrose JA Winters SL Stern A Eng A Teichholz LE Gorlin R Fuster V Angiographic morphology and the pathogenesis of unstable angina pectoris.J Am Coll Cardiol. 1985; 5: 609-616Abstract Full Text PDF PubMed Scopus (682) Google Scholar, 34Bresnahan DR Davis JL Holmes Jr, DR Smith HC Angiographic occurrence and clinical correlates of intraluminal coronary artery thrombus: role of unstable angina.J Am Coll Cardiol. 1985; 6: 285-289Abstract Full Text PDF PubMed Scopus (145) Google Scholar, 35Davies MJ Thomas AC Plaque fissuring—the cause of acute myocardial infarction, sudden ischaemic death, and crescendo angina.Br Heart J. 1985; 53: 363-373Crossref PubMed Google Scholar, 36Sherman CT Litvack F Grundfest W Lee M Hickey A Chaux A Kass R Blanche C Matloff J Morgenstern L Ganz W Swan HJC Forrester J Coronary angioscopy in patients with unstable angina pectoris.N Engl J Med. 1986; 315: 913-919Crossref PubMed Scopus (675) Google Scholar This underlying unstable arterial pathologic condition predisposes to occlusion during PTCA or to reocclusion after initially successful dilation.37Mabin TA Holmes Jr, DR Smith HC Vlietstra RE Bove AA Reeder GS Chesebro JH Bresnahan JF Orszulak TA Intracoronary thrombus: role in coronary occlusion complicating percutaneous transluminal coronary angioplasty.J Am Coll Cardiol. 1985; 5: 198-202Abstract Full Text PDF PubMed Scopus (275) Google Scholar, 38Sugrue DD Holmes Jr, DR Smith HC Reeder GS Lane GE Vlietstra RE Bresnahan JF Hammes LN Piehler JM Coronary artery thrombus as a risk factor for acute vessel occlusion during percutaneous transluminal coronary angioplasty: improving results.Br Heart J. 1986; 56: 62-66Crossref PubMed Scopus (97) Google Scholar This outcome can usually be managed with repeat dilation. In such patients, adjunctive treatments such as antiplatelet agents, anticoagulants, and even lytic therapy may play a more important role than in patients with stable angina. A special circumstance is acute myocardial infarction (Fig. 3). In these patients, the typical angiographic finding is acute thrombotic occlusion of the infarct-related artery. PTCA may be used alone to disperse the thrombus mechanically and treat the underlying atheromatous lesion.39O'Neill W Timmis GC Bourdillon PD Lai P Ganghadarhan V Walton Jr, J Ramos R Laufer N Gordon S Schork MA Pitt B A prospective randomized clinical trial of intracoronary streptokinase versus coronary angioplasty for acute myocardial infarction.N Engl J Med. 1986; 314: 812-818Crossref Pub
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