Aortic Valvuloplasty: Are Balloon-Dilated Valves All They Are “Cracked” Up To Be?
1988; Elsevier BV; Volume: 63; Issue: 8 Linguagem: Inglês
10.1016/s0025-6196(12)62366-0
ISSN1942-5546
Autores Tópico(s)Cardiovascular Issues in Pregnancy
ResumoAs evidenced in drawings by Leonardo da Vinci,1O'Malley CD Saunders JB de CM Leonardo da Vinci on the Human Body. Henry Schuman, New York1952: 263Google Scholar the fact that the aortic valve may be rendered pathologic by extensive calcific deposits has been recognized for almost half a millenium. The physiologic implications of such aortic valvular calcific deposits, of course, were not appreciated for some time—200 to 400 years.2McGinn S White PD Clinical observations on aortic stenosis.Am J Med Sci. 1934; 188: 1-15Crossref Google Scholar, 3Contratto AW Levine SA Aortic stenosis with special reference to angina pectoris and syncope.Ann Intern Med. 1937; 10: 1636-1653Crossref Google Scholar Seen in this perspective, attempts to alter or altogether replace calcified, stenotic aortic valves represent a relatively recent flurry of activity spanning a mere 3 to 4 decades. Initial interventions designed to treat calcific aortic stenosis were not elegant. In 1913, Tuffier4Tuffier T: État actuel de la chirugie intrathoracique. Trans Int Cong Med London, 1913. Section 7: Surgery, Part 2, 1914, p 249Google Scholar attempted a truly closed commissurotomy by digitally invaginating a portion of the ascending aortic wall through the orifice of a heavily calcified aortic valve. In 1947, Smithy and Parker5Smithy HG Parker EF Experimental aortic valvulotomy.Surg Gynecol Obstet. 1947; 84: 625-628PubMed Google Scholar reported a series of experimental operations in which a thin-bladed knife with a distal hook was used to lacerate one or more aortic valve cusps by means of a transventricular approach. Bailey6Bailey CP Surgery of the Heart. Lea & Febiger, Philadelphia1955: 740-742Google Scholar briefly considered a similar approach with use of a Goodell uterine dilator, before opting for a transaortic commissurotomy performed through the right common carotid artery with three umbrella-like dilating springs mounted on a straight probe. The results left Bailey convinced that “…blind retrograde performance of aortic commissurotomy was inherently unsound and could never be surgically acceptable.” Although subsequent attempts to perform a “modified” closed commissurotomy through a supravalvular prosthetic pouch7Harken DE Black H Taylor WJ Thrower WB Soroff HS The surgical correction of calcific aortic stenosis in adults: results in the first 100 consecutive transaortic valvuloplasties.J Thorac Surg. 1958; 36: 759-776PubMed Google Scholar, 8Harken DE Black H Taylor WJ Thrower WB Soroff HS Bush V The surgical correction of calcific aortic stenosis in adults. I. Technique of transaortic valvuloplasty.Am J Cardiol. 1959; 4: 135-146Abstract Full Text PDF PubMed Scopus (4) Google Scholar were associated with a reduction in operative mortality (17.5%) and improved relief of symptoms for up to 4 years postoperatively,9Abelmann WH Ellis LB Severe aortic stenosis in adults: evaluation by clinical and physiologic criteria, and results of surgical treatment.Ann Intern Med. 1959; 51: 449-460Crossref PubMed Scopus (12) Google Scholar postmortem studies by McMillan10McMillan IKR Aortic stenosis: a post-mortem cinephotographic study of valve action.Br Heart J. 1955; 17: 56-62Crossref PubMed Scopus (13) Google Scholar and subsequent experience with these early operative approaches reconvinced Bailey that his earlier conclusion had indeed been correct: “… we do not accomplish much opening of the stenotic valve by any closed method. It is not surprising that many of our surviving patients are beginning to show evidences of recurrence of the stenosis….”7Harken DE Black H Taylor WJ Thrower WB Soroff HS The surgical correction of calcific aortic stenosis in adults: results in the first 100 consecutive transaortic valvuloplasties.J Thorac Surg. 1958; 36: 759-776PubMed Google Scholar For this reason, Bailey proposed an exclusively open procedure—“… a painstaking technique, somewhat analogous to soap sculpture … to remove the extremely … calcified layer.”7Harken DE Black H Taylor WJ Thrower WB Soroff HS The surgical correction of calcific aortic stenosis in adults: results in the first 100 consecutive transaortic valvuloplasties.J Thorac Surg. 1958; 36: 759-776PubMed Google Scholar Shortly thereafter, Kirklin and Mankin11Kirklin JW Mankin HT Open operation in the treatment of calcific aortic stenosis.Circulation. 1960; 21: 578-586Crossref PubMed Scopus (12) Google Scholar at the Mayo Clinic and Hufnagel and Conrad12Hufnagel CA Conrad PW Calcific aortic stenosis.N Engl J Med. 1962; 266: 72-76Crossref PubMed Scopus (8) Google Scholar at Georgetown took full advantage of the more open exposure and increased operative time permitted by the advent of cardiopulmonary bypass to perform a less hasty, more thorough manual débridement using the approach outlined by Bailey. These surgeons published clinical and hemodynamic data that substantiated the efficacy of such a surgical procedure for calcific aortic stenosis. The era of operative valvuloplasty, however, came to a crashing, albeit temporary, halt as more “radical” treatments of aortic stenosis, consisting of valvulectomy and prosthetic replacement, came into vogue. The variety of prostheses developed and implanted during the next 30 years was a testimony to both the imagination of a series of surgical pioneers and the validity of the emperor's-new-clothes syndrome: despite expectations that each new device would finally combine durability, freedom from thrombotic and even infectious complications, and superior hemodynamic performance, no prosthesis proved ideal13Roberts WC Bulkley BH Morrow AG Pathologic anatomy of cardiac valve replacement: a study of 224 necropsy patients.Prog Cardiovasc Dis. 1973; 15: 539-587Abstract Full Text PDF PubMed Scopus (91) Google Scholar once subjected to the test of time. As a result, an interest in preserving the baby with the bathwater began to percolate among surgeons and nonsurgeons alike. In vitro studies in our laboratory demonstrated that heavily calcified, three-cuspid aortic valves could be expeditiously débrided by using carbon dioxide laser irradiation.14Isner JM Michlewitz H Clarke RH Donaldson RF Konstam MA Salem DN Laser-assisted debridement of aortic valve calcium.Am Heart J. 1985; 109: 448-452Abstract Full Text PDF PubMed Scopus (19) Google Scholar King and associates15King RM Pluth JR Giuliani ER Piehler JM Mechanical decalcification of the aortic valve.Ann Thorac Surg. 1986; 42: 269-272Abstract Full Text PDF PubMed Scopus (32) Google Scholar at the Mayo Clinic and Mindich and colleagues16Mindich BP Guarino T Goldman ME Aortic valvuloplasty for acquired aortic stenosis.Circulation. 1986; 74: I130-I135PubMed Google Scholar at St. Luke's-Roosevelt Hospital in New York pursued manual débridement of aortic valvular calcific deposits. Perhaps as a result of careful selection of valvular morphologic features and also intraoperative echocardiographic monitoring of valvular insufficiency and leaflet mobility,17Goldman ME Fuster V Guarino T Mindich BP Intraoperative echocardiography for the evaluation of valvular regurgitation: experience in 263 patients.Circulation. 1986; 74: I143-I149PubMed Google Scholar certain patients did exceptionally well with this approach. Of 23 patients who underwent operation and subsequent follow-up for as long as 6 years in a study by Mindich and co-workers,16Mindich BP Guarino T Goldman ME Aortic valvuloplasty for acquired aortic stenosis.Circulation. 1986; 74: I130-I135PubMed Google Scholar none had embolic complications, the mean valve area increased from 0.55 ± 0.05 cm2 to 1.56 ± 0.05 cm2, and only 1 patient had evidence of restenosis. In the midst of these attempts, however, two groups of interventional cardiologists borrowed a page from the book being written by pediatric cardiologists in their attempts to treat congenital valvular stenosis by percutaneous balloon dilation.18Lababidi Z Wu J-R Walls JT Percutaneous balloon aortic valvuloplasty: results in 23 patients.Am J Cardiol. 1984; 53: 194-197Abstract Full Text PDF PubMed Scopus (314) Google Scholar To the surprise of almost everyone, Cribier and associates19Cribier A Saoudi N Berland J Savin T Rocha P Letac B Percutaneous transluminal valvuloplasty of acquired aortic stenosis in elderly patients: an alternative to valve replacement?.Lancet. 1986; 1: 63-67Abstract PubMed Google Scholar in France and McKay and colleagues20McKay RG Safian RD Lock JE Mandell VS Thurer RL Schnitt SJ Grossman W Balloon dilatation of calcific aortic stenosis in elderly patients: postmortem, intraoperative, and percutaneous valvuloplasty studies.Circulation. 1986; 74: 119-125Crossref PubMed Scopus (196) Google Scholar in the United States demonstrated that even calcified valves in adults with aortic stenosis were amenable to balloon dilation. Subsequent studies21Isner JM Salem DN Desnoyers MR Hougen TJ Mackey WC Pandian NG Eichhorn EJ Konstam MA Levine HJ Treatment of calcific aortic stenosis by balloon valvuloplasty.Am J Cardiol. 1987; 59: 313-317Abstract Full Text PDF PubMed Scopus (82) Google Scholar, 22Schneider JF Wilson M Gallant TE Percutaneous balloon aortic valvuloplasty for aortic stenosis in elderly patients at high risk for surgery.Ann Intern Med. 1987; 106: 696-699Crossref PubMed Scopus (35) Google Scholar, 23Cribier A Savin T Berland J Rocha P Mechmeche R Saoudi N Behar P Letac B Percutaneous transluminal balloon valvuloplasty of adult aortic stenosis: report of 92 cases.J Am Coll Cardiol. 1987; 9: 381-386Abstract Full Text PDF PubMed Scopus (183) Google Scholar, 24McKay RG Safian RD Lock JE Diver DJ Berman AD Warren SE Come PC Baim DS Mandell VE Royal HD Grossman W Assessment of left ventricular and aortic valve function after aortic balloon valvuloplasty in adult patients with critical aortic stenosis.Circulation. 1987; 75: 192-203Crossref PubMed Scopus (98) Google Scholar in many hundreds of patients confirmed that, in the vast majority of such cases, balloon dilation clearly produces immediate hemodynamic improvement. The fact that many, if not most, patients had hemodynamic findings after valvuloplasty that still constituted “critical” aortic stenosis25Grossman W Cardiac Catheterization and Angiography. Third edition. Lea & Febiger, Philadelphia1986: 369Google Scholar was tolerated for several reasons. First, most of the early patients were poor or nonsurgical candidates; thus, balloon valvuloplasty was their sole option. Second, investigators anticipated that the use of bigger or multiple balloons (or both) would produce greater hemodynamic improvement. Third, as certain surgeons had noted 3 decades earlier, a “… small … increase of the effective aortic orifice can bring about considerable clinical improvement.”11Kirklin JW Mankin HT Open operation in the treatment of calcific aortic stenosis.Circulation. 1960; 21: 578-586Crossref PubMed Scopus (12) Google Scholar Initial reports, in fact, confirmed that modest hemodynamic improvement was sufficient to accomplish substantial clinical improvement in most patients.19Cribier A Saoudi N Berland J Savin T Rocha P Letac B Percutaneous transluminal valvuloplasty of acquired aortic stenosis in elderly patients: an alternative to valve replacement?.Lancet. 1986; 1: 63-67Abstract PubMed Google Scholar, 20McKay RG Safian RD Lock JE Mandell VS Thurer RL Schnitt SJ Grossman W Balloon dilatation of calcific aortic stenosis in elderly patients: postmortem, intraoperative, and percutaneous valvuloplasty studies.Circulation. 1986; 74: 119-125Crossref PubMed Scopus (196) Google Scholar, 21Isner JM Salem DN Desnoyers MR Hougen TJ Mackey WC Pandian NG Eichhorn EJ Konstam MA Levine HJ Treatment of calcific aortic stenosis by balloon valvuloplasty.Am J Cardiol. 1987; 59: 313-317Abstract Full Text PDF PubMed Scopus (82) Google Scholar, 22Schneider JF Wilson M Gallant TE Percutaneous balloon aortic valvuloplasty for aortic stenosis in elderly patients at high risk for surgery.Ann Intern Med. 1987; 106: 696-699Crossref PubMed Scopus (35) Google Scholar, 23Cribier A Savin T Berland J Rocha P Mechmeche R Saoudi N Behar P Letac B Percutaneous transluminal balloon valvuloplasty of adult aortic stenosis: report of 92 cases.J Am Coll Cardiol. 1987; 9: 381-386Abstract Full Text PDF PubMed Scopus (183) Google Scholar, 24McKay RG Safian RD Lock JE Diver DJ Berman AD Warren SE Come PC Baim DS Mandell VE Royal HD Grossman W Assessment of left ventricular and aortic valve function after aortic balloon valvuloplasty in adult patients with critical aortic stenosis.Circulation. 1987; 75: 192-203Crossref PubMed Scopus (98) Google Scholar Unfortunately, more recent data26Desnoyers MR, Isner JM, Wong SS, Pandian NG, Eichhorn EJ, Hougen TJ, Fields CD, Lucas AR, Salem DN: Clinical and non-invasive hemodynamic results after aortic balloon valvuloplasty for aortic stenosis. Am J Cardiol (in press)Google Scholar, 27Block PC Waldman H Palacios IF Follow-up of patients having percutaneous aortic valvuloplasty (PAV) (abstract).Circulation. 1987; 76: IV496Google Scholar, 28Schneider JF Wilson MA Restenosis is common six months after balloon valvuloplasty for calcific aortic stenosis in adults (abstract).Circulation. 1987; 76: IV745Google Scholar suggest that the latter seems to persist longer than the former. Furthermore, even when dual balloon valvuloplasty has been proved to augment aortic valve area in excess of that which can be accomplished with single balloon dilation,29Isner JM Salem DN Desnoyers MR Fields CD Halaburka KR Slovenkai GA Hougen TJ Eichhorn EJ Rosenfield K Dual balloon technique for valvuloplasty of aortic stenosis in adults.Am J Cardiol. 1988; 61: 583-589Abstract Full Text PDF PubMed Scopus (17) Google Scholar preliminary follow-up suggests that the incidence of restenosis is not diminished.30Fields CD, Lucas A, Desnoyers MR, Pandian NG, Caldiera M, Salem DN, Isner JM: Follow-up of patients treated with dual balloon valvuloplasty for aortic stenosis: no improvement in restenosis (abstract). Clin Res (in press)Google Scholar Although recent data31O'Keefe Jr, JH Vlietstra RE Bailey KR Holmes Jr, DR Natural history of candidates for balloon aortic valvuloplasty.Mayo Clin Proc. 1987; 62: 986-991Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar, 32Kelly TA Rothbart RM Cooper CM Kaiser DL Smucker ML Gibson RS Comparison of outcome of asymptomatic to symptomatic patients older than 20 years of age with valvular aortic stenosis.Am J Cardiol. 1988; 61: 123-130Abstract Full Text PDF PubMed Scopus (236) Google Scholar suggest that symptomatic status may be the preferred metric by which to judge the need for therapy in elderly patients with aortic stenosis, the lingering threat of sudden unexpected death33Frank S Johnson A Ross Jr, J Natural history of valvular aortic stenosis.Br Heart J. 1973; 35: 41-46Crossref PubMed Scopus (235) Google Scholar currently makes it difficult to recommend percutaneous balloon valvuloplasty for younger patients who may return to a schedule of vigorous exercise with residual or recurrent “critical” aortic stenosis.34Rahimtoola SH Catheter balloon valvuloplasty of aortic and mitral stenosis in adults: 1987.Circulation. 1987; 75: 895-901Crossref PubMed Scopus (62) Google Scholar Part and parcel of the difficulty in judging the ultimate potential of balloon valvuloplasty involved the enigmatic mechanism by which the procedure works. It is clearly not essential that the mechanism by which an intervention is successful be fully understood in order to recommend it—the efficacy of balloon angioplasty, for example, was apparent well before general agreement existed about the means by which luminal patency was improved.35Waller BF Pathology of transluminal balloon angioplasty used in the treatment of coronary heart disease.Hum Pathol. 1987; 18: 476-484Abstract Full Text PDF PubMed Scopus (49) Google Scholar In the case of mitral stenosis, however, the demonstration that balloon valvuloplasty augmented the area of the orifice by commissural fracture36Kaplan JD Isner JM Karas RH Halaburka KR Konstam MA Hougen TJ Cleveland RJ Salem DN In vitro analysis of mechanisms of balloon valvuloplasty of stenotic mitral valves.Am J Cardiol. 1987; 59: 318-323Abstract Full Text PDF PubMed Scopus (60) Google Scholar was encouraging because a wealth of surgical experience had shown that such a mechanism generally yielded a favorable long-term result. Such a mechanism is an unlikely explanation for the short-term success of aortic balloon valvuloplasty because commissural fusion is not a characteristic feature of calcific aortic stenosis involving a three-cuspid valve.37Roberts WC The structure of the aortic valve in clinically isolated aortic stenosis: an autopsy study of 162 patients over 15 years of age.Circulation. 1970; 42: 91-97Crossref PubMed Scopus (146) Google Scholar, 38Edwards JE Pathology of acquired valvular disease of the heart.Semin Roentgenol. 1979; 14: 96-115Abstract Full Text PDF PubMed Scopus (13) Google Scholar Initial observations made intraoperatively or in vitro at autopsy by McKay and associates20McKay RG Safian RD Lock JE Mandell VS Thurer RL Schnitt SJ Grossman W Balloon dilatation of calcific aortic stenosis in elderly patients: postmortem, intraoperative, and percutaneous valvuloplasty studies.Circulation. 1986; 74: 119-125Crossref PubMed Scopus (196) Google Scholar, 39Safian RD Mandell VS Thurer RE Hutchins GM Schnitt SJ Grossman W McKay RG Postmortem and intraoperative balloon valvuloplasty of calcific aortic stenosis in elderly patients: mechanisms of successful dilation.J Am Coll Cardiol. 1987; 9: 655-660Abstract Full Text PDF PubMed Scopus (85) Google Scholar suggested that balloon inflation improved leaflet mobility by creating “cracks” in leaflet calcium. More recently, Kennedy and colleagues, as reported in this issue of the Proceedings (pages 769 to 776), and our own group40Isner JM Samuels DA Slovenkai GA Halaburka KR Hougen TJ Desnoyers MR Fields CD Salem DN Mechanism of aortic balloon valvuloplasty: fracture of valvular calcific deposits.Ann Intern Med. 1988; 108: 377-380Crossref PubMed Scopus (34) Google Scholar have observed similar cracks at autopsy after balloon valvuloplasty had been performed during life. With the typical bulk of such nodular deposits of leaflet calcium, are these “cracks” large enough to confer an adequate result? In the short-term perspective, perhaps the result is adequate; after all, the Simplon Pass—proportionately a “crack” relative to the Alps through which it was tunneled—has proved an unqualified success. The finding, however, that these cracks may be “closed” by granulation tissue (Fig. 1) suggests that the long-term benefit of such limited architectural alteration will be every bit as limited as Bailey predicted any closed procedure would be. Kennedy and co-workers have further drawn attention to another group of patients in whom this intervention apparently is ineffective, even on a short-term basis—namely, patients with a congenitally bicuspid aortic valve. Among the almost 100 patients in whom we have performed aortic valvuloplasty, in only 4 has balloon dilation failed to produce acute hemodynamic improvement, and 3 were ultimately shown (at the time of aortic valve replacement) to have a congenitally bicuspid aortic valve.21Isner JM Salem DN Desnoyers MR Hougen TJ Mackey WC Pandian NG Eichhorn EJ Konstam MA Levine HJ Treatment of calcific aortic stenosis by balloon valvuloplasty.Am J Cardiol. 1987; 59: 313-317Abstract Full Text PDF PubMed Scopus (82) Google Scholar, 41Fields CD, Isner JM: Balloon valvuloplasty in adults. In. Cardiology Clinics: Interventional Cardiology. Edited by MW Clemen, HS Cabin. Philadelphia, WB Saunders Company (in press)Google Scholar Why the bicuspid valve is less amenable to balloon dilation is not entirely clear, but the outcome may be due in part to the relatively greater arc of attachment of each of the two, as opposed to three, cusps (Fig. 2) or the more recently noted histoarchitectural differences in the distribution of leaflet calcium in congenitally bicuspid versus three-cuspid aortic valves.42Braimen J DeFranco A Halaburka KR Slovenkai GA Donaldson RF Fields CD Isner JM Contrasting histoarchitecture of calcific deposits in leaflets from bicuspid versus tricuspid aortic valves (abstract).Lab Invest. 1988; 58: 12AGoogle Scholar Moreover, Kennedy and associates point out that the congenitally bicuspid aortic valve may, in fact, constitute a distinct liability for balloon valvuloplasty, because of the risk of irreversible hypotension associated with balloon dilation. In the fourth of our aforementioned patients, irreversible hypotension developed after balloon inflation; at autopsy, the patient was found to have a congenitally bicuspid aortic valve.41Fields CD, Isner JM: Balloon valvuloplasty in adults. In. Cardiology Clinics: Interventional Cardiology. Edited by MW Clemen, HS Cabin. Philadelphia, WB Saunders Company (in press)Google Scholar When in vitro balloon inflation of this patient's calcified, stenotic valve was performed at autopsy (Fig. 3), the balloon was noted to occupy the entire orifice in a manner that appeared likely to obstruct antegrade blood flow altogether; this finding contrasts notably with the three-cuspid valve in which antegrade blood flow typically persists at the “corners” of each commissure.19Cribier A Saoudi N Berland J Savin T Rocha P Letac B Percutaneous transluminal valvuloplasty of acquired aortic stenosis in elderly patients: an alternative to valve replacement?.Lancet. 1986; 1: 63-67Abstract PubMed Google Scholar Unfortunately, conventional imaging techniques cannot establish whether an aortic valve, once heavily calcified, is or is not congenitally bicuspid. Therefore, it remains possible that the cumulative experience with balloon aortic valvuloplasty reported to date would be associated with better hemodynamic results and fewer complications if patients with “surreptitious” bicuspid aortic valves could be eliminated from such an analysis. Because the experience with aortic balloon valvuloplasty is still relatively limited and because further improvements in technique and instrumentation will undoubtedly be developed, one needs to remain sanguine about the future of this procedure. To paraphrase what Samuel Johnson once observed about a dog walking on its two hind legs, what is remarkable about balloon aortic valvuloplasty is not whether it works well, but that it works at all. At the very least, a niche for balloon aortic valvuloplasty seems to have been carved into the interventional armamentarium for the treatment of patients who are either flatly unable to undergo or are at extremely high risk for aortic valve replacement as well as for patients who are in extremis, for whom it may serve as a “bridge” to surgical treatment.43Desnoyers MR Salem DN Rosenfield K Mackey W O'Donnell T Isner JM Treatment of cardiogenic shock by emergency aortic balloon valvuloplasty.Ann Intern Med. 1988; 108: 833-835Crossref PubMed Scopus (28) Google Scholar On the other hand, the results accomplished during the past decade with open débridement of calcified aortic valves have clearly established a legitimate role for this approach to preserving the native valve and thereby obviating the risks associated with prosthetic devices. Indeed, the most recent experience with the Cavitron ultrasonic surgical aspirator44Freeman WK Schaff HV King RM Orszulak TA Ultrasonic aortic valve decalcification: Doppler echocardiographic evaluation (abstract).J Am Coll Cardiol. 1988; 11: 229AGoogle Scholar seems likely to make intraoperative calcific débridement even more feasible than had been previously possible with conventional surgical instruments. Whether or not the balloon for aortic valvuloplasty will go the way of the Goodell uterine dilator remains to be seen. At present, however, the validity of Bailey's conclusions about the futility of a closed technique for the treatment of calcific aortic stenosis does not seem in serious jeopardy.
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