Percutaneous Balloon Mitral Valvuloplasty
2008; Lippincott Williams & Wilkins; Volume: 119; Issue: 8 Linguagem: Finlandês
10.1161/circulationaha.108.792952
ISSN1524-4539
AutoresMasakiyo Nobuyoshi, Takeshi Arita, Shin-ichi Shirai, Naoya Hamasaki, Hiroyoshi Yokoi, Masashi Iwabuchi, Hitoshi Yasumoto, Hideyuki Nosaka,
Tópico(s)Infective Endocarditis Diagnosis and Management
ResumoHomeCirculationVol. 119, No. 8Percutaneous Balloon Mitral Valvuloplasty Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBPercutaneous Balloon Mitral ValvuloplastyA Review Masakiyo Nobuyoshi, MD, Takeshi Arita, MD, Shin-ichi Shirai, MD, Naoya Hamasaki, MD, Hiroyoshi Yokoi, MD, Masashi Iwabuchi, MD, Hitoshi Yasumoto, MD and Hideyuki Nosaka, MD Masakiyo NobuyoshiMasakiyo Nobuyoshi From Kokura Memorial Hospital (M.N., T.A., S.S., H. Yokoi, M.I. H. Yasumoto, H.N.) and Hamasaki Cardiology Clinic (N.H.), Kitakyushu, Japan. , Takeshi AritaTakeshi Arita From Kokura Memorial Hospital (M.N., T.A., S.S., H. Yokoi, M.I. H. Yasumoto, H.N.) and Hamasaki Cardiology Clinic (N.H.), Kitakyushu, Japan. , Shin-ichi ShiraiShin-ichi Shirai From Kokura Memorial Hospital (M.N., T.A., S.S., H. Yokoi, M.I. H. Yasumoto, H.N.) and Hamasaki Cardiology Clinic (N.H.), Kitakyushu, Japan. , Naoya HamasakiNaoya Hamasaki From Kokura Memorial Hospital (M.N., T.A., S.S., H. Yokoi, M.I. H. Yasumoto, H.N.) and Hamasaki Cardiology Clinic (N.H.), Kitakyushu, Japan. , Hiroyoshi YokoiHiroyoshi Yokoi From Kokura Memorial Hospital (M.N., T.A., S.S., H. Yokoi, M.I. H. Yasumoto, H.N.) and Hamasaki Cardiology Clinic (N.H.), Kitakyushu, Japan. , Masashi IwabuchiMasashi Iwabuchi From Kokura Memorial Hospital (M.N., T.A., S.S., H. Yokoi, M.I. H. Yasumoto, H.N.) and Hamasaki Cardiology Clinic (N.H.), Kitakyushu, Japan. , Hitoshi YasumotoHitoshi Yasumoto From Kokura Memorial Hospital (M.N., T.A., S.S., H. Yokoi, M.I. H. Yasumoto, H.N.) and Hamasaki Cardiology Clinic (N.H.), Kitakyushu, Japan. and Hideyuki NosakaHideyuki Nosaka From Kokura Memorial Hospital (M.N., T.A., S.S., H. Yokoi, M.I. H. Yasumoto, H.N.) and Hamasaki Cardiology Clinic (N.H.), Kitakyushu, Japan. Originally published23 Dec 2008https://doi.org/10.1161/CIRCULATIONAHA.108.792952Circulation. 2009;119:e211–e219Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: December 23, 2008: Previous Version 1 Several diseases have been acknowledged as pathological causes for mitral valve stenosis (MS), of which rheumatic heart disease is the most prevalent. Rheumatic heart disease is a chronic manifestation of rheumatic carditis, which occurs in 60% to 90% of cases of rheumatic fever. Rheumatic fever is a late sequela to Group A β-hemolytic streptococcal infection of the throat. The initial rheumatic fever results only in an edematous inflammatory process, leading to the fibrinoid necrosis of the connective tissue and cellular reactions. The initial valvulitis results in verruciform deposition of fibrin along the closing portion of the leaflets. Although all of the cardiac valves may be involved by this rheumatic process, the mitral valve is involved most prominently. The endocardial lesion most often leaves permanent sequela resulting in valvular regurgitation, stenosis, or both. Stenosis of this valve occurs from leaflet thickening, commissural fusion, and chordal shortening/fusion due to the above described pathological process.Rheumatic Heart Valve Disease Is Still Epidemic in AsiaThe decrease of the incidence of rheumatic heart disease in developed countries had already begun in 1910, and it is now below 1.0 per 100 000. On the other hand, the occurrence rate of rheumatic heart disease in developing countries remains substantial. Because the decline in the prevalence of rheumatic fever in industrialized nations started even before the era of penicillin and thus was related to improved living standards, the continued prevalence of rheumatic heart disease in undeveloped or developing countries is related not only to the limited availability of penicillin but to their socioeconomic status (ie, overpopulation, overcrowding, poverty, and poor access to medical care).According to the annual report by the World Heart Federation, an estimated 12 million people are currently affected by rheumatic fever and rheumatic heart disease worldwide, and high incidence rates are reported in the Southern Pacific Islands. Several studies were conducted on the prevalence of rheumatic heart disease, reporting 0.14/1000 in Japan,1 1.86/1000 in China,2 0.5/1000 in Korea,3 4.54/1000 in India,4 and 1.3/1000 in Bangladesh.5In rapidly evolving Asian countries, awareness of rheumatic heart disease has prevailed along with the widespread use of transthoracic echocardiography. Furthermore, demands for adequate medical therapies are expanding in tandem with explosive socioeconomic growth that may contribute to expanding use of percutaneous balloon mitral valvuloplasty (PBMV).Percutaneous Balloon Mitral Valvuloplasty: The ConceptBefore the advent of PBMV, most patients with symptomatic MS were treated with surgical mitral commissurotomy, either open or closed. Closed mitral commissurotomy was first described by Harken and Bailey in the late 1940s.6 Subsequently, after the development of cardiopulmonary bypass, the open surgical commissurotomy replaced the closed technique in most countries in the late 1960s and early 1970s. In 1982, Kanji Inoue, a Japanese cardiac surgeon, first developed the idea that a degenerated mitral valve could be inflated using a balloon made of strong yet pliant natural rubber.7 This concept was similar to the already abandoned closed surgical technique at that time. At first, this unique technique was largely limited to the Far East Asia, whereas in most of the other countries traditional cylindrically shaped balloons, which were initially developed for pulmonic valvuloplasty, were utilized for mitral valvuloplasty. Lock et al8 in India first reported the use of such a cylindrical balloon for mitral valvuloplasty. Subsequently, the idea of a double-balloon technique was introduced from Saudi Arabia9 as a potential alternative method for balloon commissurotomy. The double-balloon technique requires that 2 guidewires be positioned in the left ventricular apex, through which 2 floating balloon catheters are then advanced across the mitral valve orifice. Although the double-balloon technique is surely effective, it is more technically demanding and thus often requires a longer procedure time, which may lead to inadvertent complications. The guidewire positioned in the left ventricular apex sometimes induces perforation of the apex, leading to cardiac tamponade. In fact, PBMV using a single Inoue balloon yields equivalent efficacy when compared with the double-balloon technique and with lower procedural risks.10 Today, therefore, Inoue's single-balloon technique has become the most popular method for performing PBMV in most parts of the world.The mechanism of PBMV is the same as the already abandoned closed mitral commissurotomy.11 Pathological studies have disclosed that the main mechanism of successful PBMV is a fracture of the commissures. In comparison to surgical mitral commissurotomy, PBMV has shown equal or better12,13 success rates and comparable restenosis rates.13 Randomized trials comparing PBMV to closed commissurotomy have shown that PBMV is superior to closed commissurotomy, providing a larger valve area and better long-term durability.14Echocardiography Plays a Major Role in Patient Selection for PBMVIndications for PBMVThe management of symptomatic and severe MS is described comprehensively in recent guidelines published jointly by the American Heart Association (AHA) and the American College of Cardiology (ACC)15 and in guidelines published by the European Society of Cardiology (ESC)16 (Figure 1). Download figureDownload PowerPointFigure 1. ACC/AHA guidelines in 2007 advocate earlier use of PBMV for symptomatic patients with MS in cases where the valve morphology is adequate. H&P indicates history and physical; CXR, chest x-ray; ECHO, echocardiogram; MVA, mitral valve area; PASP, pulmonary artery systolic pressure; PAWP, pulmonary artery wedge pressure; MVG, mitral valve gradient; and PH, pulmonary hypertension. Adapted from Bonow et al15 with permission from the American Heart Association. Copyright 2006 by the American College of Cardiology Foundation and the American Heart Association, Inc.In the case of moderate or severe MS, one has to assess the anatomy of the mitral valve meticulously with regard to the feasibility and safety of PBMV. As shown in Table 1, the most widely used echocardiographic parameter is the Wilkins score, which takes into consideration the anatomy of the leaflet, the commissures, and the subvalvular apparatus.17 The scoring system assigns a point value from 1 to 4 for each of (1) valve calcification, (2) leaflet mobility, (3) leaflet thickening, and (4) subvalvular apparatus degeneration. A mitral valve with a score 9 to 10, especially with more than moderate mitral regurgitation, surgical therapy should be advised except in cases with serious comorbidities. Table 1. Wilkins ScoreGradeMobilityThickeningCalcificationSubvalvular ThickeningAdapted from Wilkins et al17 with permission from BMJ Publishing Group Ltd. Copyright 1988 BMJ Publishing Group Ltd and British Cardiovascular Society.1Highly mobile with only leaflet tips restrictedLeaflets near normal in thickness (4–5 mm)A single area of increased echo brightnessMinimal thickening just below the mitral leaflets2Leaflet mid portions and base portions have normal mobilityMidleaflets normal, considerable thickening of margins (5–8 mm)Scattered areas of brightness confined to leaflet marginsThickening of chordal structures extending to one of the chordal length3Valve continues to move forward in diastole, mainly from the baseThickening extending through the entire leaflets (5–8 mm)Brightness extending into the mid portions of the leafletsThickening extended to distal third of the chords4No or minimal forward movement of the leaflets in diastoleConsiderable thickening of all leaflet tissue (>8–10 mm)Extensive brightness throughout much of the leaflet tissueExtensive thickening and shortening of all chordal structures extending down to the papillary muscleA simpler echocardiographic classification for the stenotic mitral valve is the Iung and Cormier score18 (Table 2). This score is unique for taking the length of the chordae into consideration. Table 2. Iung and Cormier ScoreGroupMitral Valve AnatomyAdapted from Iung et al18 with permission from the American Heart Association. Copyright 1996 American Heart Association.1Pliable noncalcified anterior mitral leaflet and mild subvalvular disease2Pliable noncalcified anterior mitral leaflet and severe subvalvular disease3Calcification of mitral valve of any extent, as assessed by fluoroscopy, whatever the state of the subvalvular apparatusA limitation of both scoring systems is the lack of information on the location of valve abnormalities in relation to the commissures, which may influence the results of PBMV.19,20 As PBMV theoretically helps resolve MS by splitting the commissures, a valve with a bilateral commissural fusion could benefit more fully. Conversely, a valve without any commissural fusion, in which rigid leaflets or annulus gives rise to orifice stenosis, may not benefit from commissurotomy because the leaflets or subvalvular apparatus could fracture. In addition, the presence of severe or bilateral calcification on the commissures could predict poor outcome due to worsening mitral regurgitation postprocedurally21 or a suboptimal increase in the valve area.22,23 Whichever scoring system is adopted, the success of PBMV requires that the pliability of the leaflet and the degree of degeneration and calcification of the commissures, subvalvular apparatus, annulus, and the leaflets be meticulously assessed.To detect thrombus in the left atrium or left atrial appendage, transesophageal echocardiography should be performed before performing PBMV. At our institute, we never perform PBMV if we find thrombus in the left atrium or left atrial appendage. Although some investigators have insisted that PBMV can be safely performed even when thrombus is present in the left atrial appendage,24 this therapeutic approach should be seriously discouraged. If thrombus is found, PBMV should be postponed and the patient should be started on warfarin with the prothrombin time–international normalized ratio controlled at a relatively higher level for 3 to 6 months, after which transesophageal echocardiography should be repeated to confirm the disappearance of the clot. If the thrombus has disappeared, PBMV can then be safely performed, or if the thrombus remains, surgical intervention on the mitral valve along with removal of the thrombus should be recommended.Controversies about indications for PBMV exist in cases with (1) asymptomatic moderate (mitral valve area 1.0 to 1.5 cm2) to severe (mitral valve area 1.5 cm2), and (3) symptomatic severe MS with unfavorable anatomic characteristics.In asymptomatic moderate to severe MS, both guidelines advocated that early use of PBMV be considered for patients with high risk of embolism (ESC: paroxysmal atrial fibrillation [Class IIa], history of embolism [Class IIa], evidence of atrial spontaneous contrast echo [Class IIa]; AHA/ACC: new onset of paroxysmal atrial fibrillation [Class IIb] or hemodynamic decompensation; ESC: high pulmonary artery systolic pressure [Class IIa], need for major surgery [Class IIa], and pregnancy [Class IIa]; and AHA/ACC: pulmonary hypertension at rest [Class I] or during exercise [class I] and poor exercise tolerance [Class I] when patients have favorable clinical/anatomic characteristics). If patients complain of dyspnea on exertion that is out of proportion to the degree of MS, the ACC/AHA guideline recommends use of exercise Doppler echocardiography25 to reveal occult hemodynamically significant MS.The prognostic significance of such hemodynamic compromise at exercise, however, remains unclear, and therefore application of PBMV for asymptomatic mild MS should be carefully reviewed in each case. The ACC/AHA guidelines recommend use of PBMV in these scenarios (Class IIb). On the other hand, mitral valve area >1.5 cm2 is considered one of the contraindications to PBMV according to the ESC guidelines.Although the underlying mitral valve morphology is the factor of greatest importance in determining outcome after the therapy, PBMV can be offered as the initial treatment (ESC: Class IIa, AHA/ACC: Class IIa) for selected patients with unfavorable anatomic characteristics but no unfavorable clinical characteristics (ESC: Class IIa; the ESC defines unfavorable clinical characteristics as absence of several factors: old age, New York Heart Association [NYHA] class IV, severe pulmonary hypertension, atrial fibrillation and history of commissurotomy) or have high surgical risk (AHA: Class IIa).Contraindications to PBMV are summarized in Table 3. In addition to these, a MS with no commissural fusion should be considered as a relative contraindication, as previously described. PBMV should be considered first-line therapy in most cases of severe MS without obvious contraindications.2Table 3. Contraindications to PBMVPersistent left atrial or left atrial appendage thrombusMore than moderate mitral regurgitationMassive or bicommissural calcificationSevere concomitant aortic valve diseaseSevere organic tricuspid stenosis or severe functional regurgitation with enlarged annulusSevere concomitant coronary artery disease requiring bypass surgerySelection of Appropriate Balloon SizeSelection of the appropriate balloon size is one of the most critical factors for accomplishing this procedure (ie, for releasing the stenotic mitral orifice without causing extensive damage to the commissures, leaflets, and subvalvular apparatus leading to excessive mitral regurgitation). For selecting the appropriate balloon size, some researchers have advocated methods to select balloon size with the patient's height26 or body surface area27 as a reference. A simple equation to obtain the reference size (height [cm]/10+10) has been proposed.28 The obvious point should be made, however, that the relationship of one's height to the diameter of the mitral valve orifice is not necessarily linear. Furthermore, the operator must remember that annular calcification will affect the size of the mitral valve orifice regardless of the patient's physical constitution. To avoid undesired extensive injury to the mitral valve apparatus, we select the balloon size by directly measuring the mitral annular diameter using 2-dimensional echocardiography. The mitral annular diameter can be measured on the apical 4- or 2-chamber view during mid- to end-systole. Measuring mitral annular diameter at different planes gives different values owing to the noncircular, nonplanar shape of the annulus. Theoretically, a diameter close to the distance between 2 commissures (probably annular diameter on the apical 2-chamber view) could serve as the reference size for the Inoue balloon. However, the minimal mitral annular diameter should be adopted to avoid the risk of tearing the leaflets. Figure 2 shows an example in which the diameter of the mitral valve orifice was measured at 22.8 mm. In this case, we chose a 22-mm balloon catheter, and initially we inflated the balloon to 20 mm, 2 to 3 mm smaller than the maximal balloon size. Download figureDownload PowerPointFigure 2. Measurement of mitral valve annular diameter.The PBMV ProcedureThe Inoue Balloon catheter (Toray, Tokyo, Japan) is a 12F polyvinylchloride tube with a coaxial lumina. The balloon section is stiffened and slenderized when stretched by the insertion of a metal tube. The balloon size is pressure dependent and consists of 3 portions with slightly different compliance. As pressure is gradually added, the distal portion of the balloon inflates first, followed by the proximal portion. The unique part of the Inoue balloon is its middle waist portion that has the least pressure compliance, with which fixation of the balloon catheter is facilitated and the degenerated fused commissure(s) can be dilated substantially.The procedure is always performed via a femoral approach with a 9F sheath in the vein and a 5F sheath in the artery, with the patient under light sedation. After bolus administration of 1000 U heparin, right heart catheterization is performed. Right atriography is then performed to determine the septal puncture site for the Brockenbrough needle. Transseptal catheterization is performed via a standard Brockenbrough procedure using anteroposterior views. While slowly withdrawing the Brockenbrough catheter from superior vena cava into the interatrial septum, the operator advances the Brockenbrough needle beyond the interatrial septum when the tip of the catheter falls into the fossa ovalis. Computed tomography or transesophageal echocardiography can be useful in identifying the anatomic location of the interatrial septum relative to the right atrium. Transesophageal or intracardiac echocardiography can be used not only as guidance for the Brockenbrough procedure but also as a monitor to early detect serious complications (ie, perforation and tamponade).After advancing the Brockenbrough needle, a coiled-tip guidewire is placed into the left atrium through the Brockenbrough sheath. Then, we administer 9000 U of heparin to reduce the risk of a thromboembolic event during the manipulation of catheters and wires in the left atrium. Anticoagulation time is monitored during the procedures to maintain appropriate levels of anticoagulation.In the next step, the Inoue balloon catheter is advanced over the coiled-tip wire. A system for accomplishing PBMV consists of the following devices29: Inoue balloon catheter, metallic stiffening cannula (18 gauge, 80 cm in length) for stretching and stiffening the Inoue balloon catheter, guidewire for PBMV (0.028 inches in diameter, 180 cm in length), dilator (14F polyethylene tube with a thinner tip 70 cm in length) for dilating the puncture site of the femoral vein and atrial septum, and a stylet (wire with J-shaped tip, 0.038 inches in diameter, 80 cm in length) for directing the Inoue balloon toward the mitral orifice. Once the balloon catheter has crossed the interatrial septum, the catheter should be placed in the left atrium so that the catheter forms a loop with the tip facing toward the mitral valve orifice. The tip of the balloon is inflated with 1 to 2 mL of contrast media, allowing blood flow to direct the balloon tip into the left ventricle. If advancement of the Inoue balloon proves difficult, the stylet is inserted in the balloon catheter, and the balloon catheter with stylet are moved together toward the mitral valve orifice. With the right anterior oblique view, which helps identify the proper line between the base and the apex, the deflated Inoue balloon catheter is advanced until the tip of the catheter has crossed the mitral valve into the left ventricle.Once the balloon catheter has been inserted into the left ventricle, the distal portion of the balloon is inflated with contrast media using a specially graduated syringe. The catheter is then pulled until resistance is felt. During inflation of the balloon, the appearance of a deformed distal balloon may suggest entrapment in the subvalvular apparatus. In this situation, further inflation should not be performed and the balloon should be repositioned to a location that is more proximal to the mitral orifice to avoid trauma to the subvalvular apparatus.The Inoue balloon has a much less compliant portion in its waist that assists in the secure dilatation of the mitral valve orifice. Figure 3 shows the typical step-by-step appearance of the Inoue balloon catheter. Before placing the Inoue balloon catheter, we routinely select the balloon size by which valve orifice is finally dilated, as previously described. Download figureDownload PowerPointFigure 3. Manipulation of the Inoue balloon catheter. A, Advanced deep into the left ventricle. B, Pulled with the distal portion inflated. C, Inflation of the proximal portion followed by inflation of the middle waist portion of the balloon. D, Properly inflated middle portion of the balloon securely dilates commissural.After each dilatation, the operator should obtain the left atrial pressure through the middle port of the Inoue catheter and the left ventricular pressure through the pig-tail catheter simultaneously. If the pressure gradient between the left atrial pressure and the simultaneously obtained left ventricular pressure does not decrease, the balloon size is increased in 1-mm increments until the pressure gradient decreases or substantial worsening of mitral regurgitation occurs. In addition, 2-dimensional echocardiographic observations are performed after each dilatation. To assess mitral valve orifice area after each dilatation, planimetry of the valve orifice with 2-dimensional echocardiography should be adopted rather than the pressure half-time method on continuous Doppler waveform, because pressure half-time–derived orifice area might be inaccurate in this acute setting.30If 1 of the 3 following events is encountered—decrease in the pressure gradient between the left atrium and the left ventricle, occurrence of significant mitral regurgitation, or substantial splitting of the commissure—further dilatation is not performed unless critical complications might otherwise ensue.31Immediate Results of PBMVThe binary end point of immediate procedural success is most often a final valve area >1.50 cm2 without moderate or severe mitral regurgitation. After PBMV, mitral valve area approximately doubles in most successful cases. Mitral valve anatomy as assessed by 2-dimensional echocardiography is a strong predictor of the immediate results of PBMV. The previously described Wilkins score has a discriminant cut-off point at 8 according to analyses of the immediate results of PBMV. Whatever echo scoring system is used, older age, smaller valve area, previous commissurotomy, or baseline mitral regurgitation should be considered as potential predictors for poor immediate outcome with a similar predictive strength as valve calcification.18 In clinical practice, young patients ( 1.5).Long-Term ResultsMost patients with initial procedural success report significant functional improvement. When immediate results are suboptimal, the patient's functional status does not improve or improves only transiently. Because the mechanism and background of MS may affect the long-term results of PBMV, analysis should be conducted in 2 different categories of the population: (1) in young patients with favorable valve anatomy who are the homogenous population mainly encountered in developing countries; and (2) in older patients with less-favorable valve anatomy, who are a much more heterogenous group and who are seen in Western countries.The best results of PBMV are observed in young patients who have MS with favorable anatomic characteristics (ie, pliable noncalcified valves and moderate impairment of the subvalvular apparatus). Published series from India and Tunisia have clearly demonstrated the safety and efficacy of PBMV in such patients.37,38 After PBMV, at least 90% of patients are alive without intervention on the mitral valve and with few or no symptoms 5 to 7 years after the procedure.37,38 Randomized trials conducted in these young populations show that 3- and 7-year results of PBMV are as good as those obtained with open-heart commissurotomy39 and better than those with closed-heart commissurotomy.37Fawzy et al40,41 reported an event-free survival rate of 79% at 10 years and 43% at 15 years in relatively younger patients (mean age 31±11 years) and were significantly higher for patients with optimal valve anatomy (88% at 10 years, 66% at 15 years). They found that favorable valve anatomy, age, and postprocedural mitral valve area were predictors of event-free survival.42Iung et al43 reported an event-free survival (survival with freedom from repeat PMBV, mitral valve replacement, cardiac death, high NYHA class) rate of 61% at 10 years in >1000 patients (mean age 49±14 years) with successful PBMV. Although favorable long-term prognosis largely depends on immediate procedural success, the prediction of late prognosis includes multiple factors including old age, unfavorable valve anatomy, high NYHA class, atrial fibrillation, low valve area after PBMV, high gradient after PBMV, and >grade 2 mitral regurgitation after PBMV.43,44Suboptimal immediate results lead to relatively early intervention, which explains the presence of an early drop of event-free survival after the procedure. Conversely, some patients experience late functional deterioration many years after the procedure, which is likely related to mitral restenosis.45 Post-PBMV mitral restenosis is defined as a valve area 50% loss of the initial gain in valve area.46 Reportedly, the freedom from restenosis rates were 85% at 5 years, 70% at 10 years, and 44% at 15 years and were significant
Referência(s)