Operative treatment of hypertrophic obstructive cardiomyopathy. The case against mitral valve replacement

Impact of Hospital Volume on Outcomes of Septal Myectomy for Hypertrophic Cardiomyopathy

BACKGROUND

Left ventricular outflow tract obstruction is common among symptomatic patients with hypertrophic cardiomyopathy, yet septal reduction by surgical myectomy (septal myectomy [SM]) is performed infrequently in many centers. This study examined the possible relationship between institutional case volume and early outcomes of SM.

METHODS

The Society of Thoracic Surgeons Adult Cardiac Surgery Database was queried for patients with hypertrophic cardiomyopathy who underwent SM from January 2012 to December 2019. The study defined center case volume categories as <1, 1 to 4.99, 5 to 9.99, and ≥10 cases performed on average per year.

RESULTS

The study population included 5935 patients at 481 centers with 933 surgeons. The range of average center volume was <1 to 138 cases per year. Overall early mortality was 2.6%, ventricular septal defect (VSD) occurred in 1.9%, and complete heart block occurred in 9.0%. Concomitant mitral valve (MV) repair was performed in 28.7%, and MV replacement was performed in 17.1%. In multivariable analysis, the lowest annual case volume (average <1 case/y) was consistently associated with greater early mortality (odds ratio [OR], 5.4; CI, 3.0-9.9; P < .001), greater risk of VSD (OR, 9.3; CI ,4.2-20.4; P < .001), increased incidence of complete heart block (OR, 2.0; CI, 1.5-2.7; P < .001), and a higher likelihood of MV replacement (OR, 9.4; CI, 7.5-11.8; P < .001).

CONCLUSIONS

Volume of SM cases varies widely among institutions reporting to the Society of Thoracic Surgeons Adult Cardiac Surgery Database. There appears to be an important association between surgical experience, as reflected by institutional case volume, and early outcomes, including mortality, as well as the occurrence of VSD, heart block, and MV replacement.

Ventricular Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy (Analysis Spanning 60 Years Of Practice): AJC Expert Panel

Surgical myectomy remains the time-honored primary treatment for hypertrophic cardiomyopathy patients with drug refractory limiting symptoms due to LV outflow obstruction. Based on >50 years experience, surgery reliably reverses disabling heart failure by permanently abolishing mechanical outflow impedance and mitral regurgitation, with normalization of LV pressures and preserved systolic function. A consortium of 10 international currently active myectomy centers report about 11,000 operations, increasing significantly in number over the most recent 15 years. Performed in experienced multidisciplinary institutions, perioperative mortality for myectomy has declined to 0.6%, becoming one of the safest currently performed open-heart procedures. Extended myectomy relieves symptoms in >90% of patients by ≥ 1 NYHA functional class, returning most to normal daily activity, and also with a long-term survival benefit; concomitant Cox-Maze procedure can reduce the number of atrial fibrillation episodes. Surgery, preferably performed in high volume clinical environments, continues to flourish as a guideline-based and preferred high benefit: low treatment risk option for adults and children with drug refractory disabling symptoms from obstruction, despite prior challenges: higher operative mortality/skepticism in 1960s/1970s; dual-chamber pacing in 1990s, alcohol ablation in 2000s, and now introduction of strong negative inotropic drugs potentially useful for symptom management.

Systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy: a narrative review

Background and Objective

The prevalence of hypertrophic cardiomyopathy (HCM) is estimated to be 1 in 200 to 500 individuals, with systolic anterior motion (SAM) of the mitral valve (MV) and left ventricular outflow tract (LVOT) obstruction present in 60% to 70%. In this narrative review, we aim to elucidate the pathophysiology of SAM-septal contact and LVOT obstruction in HCM by presenting a detailed review on the anatomy of the MV apparatus in HCM, examining the various existing theories pertaining to the SAM phenomenon as supported by cardiac imaging, and providing a critical assessment of management strategies for SAM in HCM.

Methods

A literature review was performed using PubMed, EMBASE, Ovid, and the Cochrane Library, of all scientific articles published through December 2021. A focus was placed on descriptive studies, reports correlating echocardiographic findings with pathologic diagnosis, and outcomes studies.

Key Content and Findings

The pathophysiology of SAM involves the complex interplay between HCM morphology, MV apparatus anatomic abnormalities, and labile hemodynamic derangements. Echocardiography and cardiac magnetic resonance (CMR) vector flow mapping have identified drag forces, as opposed to the "Venturi effect", as the main hydraulic forces responsible for SAM. The degree of mitral regurgitation with SAM is variable, and its severity is correlated with degree of LVOT obstruction and outcomes. First line therapy for the amelioration of SAM and LVOT obstruction is medical therapy with beta-blockers, non-dihydropyridine calcium-channel blockers, and disopyramide, in conjunction with lifestyle modifications. In refractory cases septal reduction therapy is performed, which may be combined with a 'resect-plicate-release' procedure, anterior mitral leaflet extension, surgical edge-to-edge MV repair, anterior mitral leaflet retention plasty, or secondary chordal cutting.

Conclusions

Recent scientific advances in the field of HCM have allowed for a maturation of our understanding of the SAM phenomenon. Cardiac imaging plays a critical role in its diagnosis, treatment, and surveillance, and in our ability to apply the appropriate therapeutic regimens. The increasing prevalence of HCM places an emphasis on continued basic and clinical research to further improve outcomes for this challenging population.

Septal Myectomy in Hypertrophic Cardiomyopathy: National Outcomes of Concomitant Mitral Surgery

OBJECTIVES

To assess the frequency and implications of mitral valve (MV) surgery at the time of septal myectomy (SM) for hypertrophic cardiomyopathy (HCM) in a national cohort.

PATIENTS AND METHODS

The National Inpatient Sample (NIS) was used to analyze surgical outcomes in patients with HCM undergoing SM from January 1, 2003, through December 31, 2014. Univariate analyses were used to compare patients undergoing SM with vs without concomitant procedures, and logistic regression was used to determine factors associated with prolonged length of stay (LOS) and in-hospital mortality. Numeric values of 10 or less were not reported per NIS data use agreements.

RESULTS

The national cohort included 1174 adults with a primary diagnosis of HCM undergoing SM. Overall mean ± SD age was 54.4±14.5 years, and 45% of patients (n=529) were male. Isolated SM was performed in 67% (n=786), and the remainder had concomitant cardiac procedures, most frequently MV repair/replacement (22%, n=257). Median LOS was increased in those with concomitant MV surgery, 7 days, compared with isolated SM, 6 days (P<.001). Overall hospital mortality was 2.9% (n=34) and was lowest in those undergoing isolated SM (<1%; P<.001). In otherwise isolated SM, MV replacement increased likelihood of in-hospital death (odds ratio, 12.0; 95% CI, 3.9-36.5; P<.001) on a univariate basis.

CONCLUSION

Intervention on the MV is more common nationally than in specialized centers, and the addition of MV replacement and other concomitant cardiac procedures was associated with increased rates of hospital mortality and LOS compared with patients undergoing isolated SM. These results suggest that concomitant MV intervention is associated with increased risk.

The 50-year history, controversy, and clinical implications of left ventricular outflow tract obstruction in hypertrophic cardiomyopathy from idiopathic hypertrophic subaortic stenosis to hypertrophic cardiomyopathy: from idiopathic hypertrophic subaortic stenosis to hypertrophic cardiomyopathy

Dynamic obstruction to left ventricular (LV) outflow was recognized from the earliest (50 years ago) clinical descriptions of hypertrophic cardiomyopathy (HCM) and has proved to be a complex phenomenon unique in many respects, as well as arguably the most visible and well-known pathophysiologic component of this heterogeneous disease. Over the past 5 decades, the clinical significance attributable to dynamic LV outflow tract gradients in HCM has triggered a periodic and instructive debate. Nevertheless, only recently has evidence emerged from observational analyses in large patient cohorts that unequivocally supports subaortic pressure gradients (and obstruction) both as true impedance to LV outflow and independent determinants of disabling exertional symptoms and cardiovascular mortality. Furthermore, abolition of subaortic gradients by surgical myectomy (or percutaneous alcohol septal ablation) results in profound and consistent symptomatic benefit and restoration of quality of life, with myectomy providing a long-term survival similar to that observed in the general population. These findings resolve the long-festering controversy over the existence of obstruction in HCM and whether outflow gradients are clinically important elements of this complex disease. These data also underscore the important principle, particularly relevant to clinical practice, that heart failure due to LV outflow obstruction in HCM is mechanically reversible and amenable to invasive septal reduction therapy. Finally, the recent observation that the vast majority of patients with HCM have the propensity to develop outflow obstruction (either at rest or with exercise) underscores a return to the characterization of HCM in 1960 as a predominantly obstructive disease.

[Evolution of the surgical strategy in hypertrophic cardiomyopathy: case studies of eight patients]

INTRODUCTION

Hypertrophic cardiomyopathy is an inherited disease characterized by a left ventricular hypertrophy, a diastolic dysfunction and rhythm troubles with risk of sudden death. There was an evolution in the surgical strategy to treat the patients who present a left ventricular outflow tract gradient.

MATERIALS AND METHODS

A retrospective study was conducted: We selected eight cases who presented an hypertrophic cardiomyopathy and operated on. Pre and post operative echocardiographic data were analysed. Follow up was obtained by call or mail to the cardiologist.

RESULTS

The patients were classified in four groups: isolated left ventricular outflow tract obstruction, left ventricular outflow tract obstruction and associated lesions, obstructive hypertrophic cardiomyopathy and endocarditis, post operative complications of the hypertrophic cardiomyopathy surgery. We observed a significant decrease of the left ventricular outflow tract mean gradient in the post operative period and at four years.

CONCLUSION

Surgical management of obstructive hypertrophic cardiomyopathy remain an important option in young patients, in case of failure of the ethanol septal ablation or in patients who present other surgical lesions. The dual chamber stimulation remain indicated in old patients.

Pathophysiology and Treatment of Hypertrophic Cardiomyopathy

All patients with hypertrophic cardiomyopathy (HCM) should have five aspects of care addressed. An attempt should be made to detect the presence or absence of risk factors for sudden arrhythmic death. If the patient appears to be at high risk, discussion of the benefits and risks of ICD are indicated, and many such patients will be implanted. Symptoms are appraised and treated. Bacterial endocarditis prophylaxis is recommended. Patients are advised to avoid athletic competition and extremes of physical exertion. First degree family members should be screened with echocardiography and ECG.

Percutaneous Versus Surgical Treatment for Patients With Hypertrophic Obstructive Cardiomyopathy and Enlarged Anterior Mitral Valve Leaflets

Background— The purpose of this study was to compare percutaneous transluminal septal myocardial ablation (PTSMA) and septal myectomy combined with mitral leaflet extension (MLE) in symptomatic hypertrophic obstructive cardiomyopathy patients with an enlarged anterior mitral valve leaflet (AMVL). Both PTSMA and myectomy reduce septal thickness and left ventricular outflow tract (LVOT) gradient; however, an uncorrected enlarged AMVL may predispose to residual systolic anterior motion (SAM) after successful standard myectomy or PTSMA. Myectomy with MLE previously demonstrated superior hemodynamic results compared with standard myectomy, but its value relative to PTSMA is unknown.

Methods and Results— Twenty-nine patients (aged 44±12 years) underwent myectomy with MLE, and 43 patients (aged 52±17 years) underwent PTSMA. Mitral leaflet area was similar in both groups (16.7±3.4 versus 15.9±2.7 cm 2 , respectively). After PTSMA, 2 patients died, 4 needed a reintervention, and 4 required a permanent pacemaker for complete heart block. After surgery, only 1 patient needed a reintervention. At 1-year follow-up, LVOT gradients did not differ between surgical and PTSMA patients (17±14 versus 23±19 mm Hg, respectively). Preinterventional mitral regurgitation grade was more severe in the surgical group, but with myectomy combined with MLE, the residual grade was similar to that of PTSMA. Mean SAM grade decreased significantly more after surgery (from 2.9±0.3 to 0.5±0.7 mm Hg versus from 2.8±0.5 to 1.3±0.9 mm Hg, P <0.05).

Conclusions— PTSMA in these selected patients with hypertrophic obstructive cardiomyopathy had more periprocedural complications and resulted in more reinterventions. Hemodynamic results (SAM grade and reduction in mitral regurgitation) were better in surgical patients.

The case for surgery in obstructive hypertrophic cardiomyopathy

Relief of left ventricular (LV) outflow obstruction in patients with hypertrophic cardiomyopathy (HCM) and disabling symptoms refractory to maximum medical management has historically been a surgical problem. Surgical septal myectomy permanently abolishes systolic anterior motion of the mitral valve and mitral regurgitation, while normalizing LV pressures and wall stress. Also, these salutary goals are achieved without encumbering patients with post-procedural devices (e.g., pacemakers or defibrillators) or creating potentially arrhythmogenic substrates, as may occur with alcohol septal ablation. Procedural morbidity and mortality risk with myectomy is similar to, and in some institutions less than those for alcohol septal ablation. Over four decades, reports from numerous centers worldwide have consistently and unequivocably documented the benefits of surgery on hemodynamic and functional state, restoring normal and acceptable quality of life to patients of all ages by largely reversing the complications of heart failure. Long-term survival after myectomy is similar to that of the general population and superior to non-operated patients with obstruction. The LV outflow tract morphology in HCM is heterogeneous and not uncommonly includes congenital anomalies of the mitral valve apparatus for which the surgeon has the flexibility to adapt the repair, often employing an extended myectomy. In the current atmosphere of increasing and perhaps excessive enthusiasm for newer catheter-based interventions, it is a critical time to promote and re-emphasize that surgery is the time-honored (and presently the most effective) treatment strategy for relieving heart failure-related disability resulting from dynamic LV outflow obstruction in HCM, and is the primary treatment option for this subgroup of severely symptomatic drug-refractory patients.

Sustained Improvement After Combined Anterior Mitral Leaflet Extension and Myectomy in Hypertrophic Obstructive Cardiomyopathy

Background— Mitral leaflet extension (MLE) combined with septal myectomy is a new surgical approach to treat hypertrophic obstructive cardiomyopathy (HOCM) and an enlarged mitral leaflet area. The study presents the long-term clinical results and outcome of this technique.

Methods and Results— MLE entails grafting a glutaraldehyde-preserved autologous pericardial patch onto the center portion of the anterior mitral valve leaflet. Twenty-nine patients with HOCM were studied. Mean follow-up (±SD) was 3.4±2.1 years (range 3 months to 7.7 years). The preoperative calculated mitral leaflet area was 16.7±3.4 cm 2 . New York Heart Association functional class improved significantly from 2.8±0.4 to 1.3±0.4 ( P <0.05), width of the interventricular septum decreased from 23±4 to 17±2 mm ( P <0.05), left ventricular outflow tract gradient decreased from 100±20 to 17±14 mm Hg ( P <0.01), severity of mitral regurgitation graded on a scale from 0 to 4+ decreased from 2.5±0.9 to 0.5±0.6 ( P <0.01), and severity of the systolic anterior motion of the mitral valve graded on a scale from 0 to 3+ decreased from 2.9±0.3 to 0.5±0.7 ( P <0.01) postoperatively. There were no deaths associated with surgery.

Conclusions— Long-term follow-up shows sustained improvement in functional status, reduction of outflow tract obstruction, and attenuation of mitral regurgitation and systolic anterior motion of the mitral valve. In this respect, the new technique widens the surgical applications in HOCM.

Obstructive hypertrophic cardiomyopathy: echocardiography, pathophysiology, and the continuing evolution of surgery for obstruction

Our understanding of the pathophysiology of obstruction in hypertrophic cardiomyopathy has evolved since initial descriptions in the late 1950s. This review addresses the cause of obstruction, from early ideas that a muscular outflow tract sphincter was the cause, through the discovery of systolic anterior motion (SAM) of the mitral valve, to current understanding that flow drag, the pushing force of flow, is the dominant hydrodynamic mechanism for SAM. The continuing redesign and modification of surgical procedures to relieve outflow obstruction have corresponded to ideas about the cause of this condition. In this review we discuss the evolution of surgical procedures to relieve obstruction and review modern surgical approaches. Medical and nonsurgical methods for reducing obstruction are reviewed, as well as efforts to prevent sudden arrhythmic cardiac death. Echocardiography has become central to understanding this complex phenomenon, and for clinical diagnosis, operative planning and intraoperative management.

Initial results of combined anterior mitral leaflet extension and myectomy in patients with obstructive hypertrophic cardiomyopathy

OBJECTIVES

The purpose of this study was to describe the clinical and functional results of combined anterior mitral leaflet extension and myectomy in patients with hypertrophic obstructive cardiomyopathy.

BACKGROUND

Septal myectomy is the most commonly performed surgical procedure in patients with hypertrophic cardiomyopathy and left ventricular outflow tract obstruction. Because of the role of the mitral valve in creating the outflow tract gradient, mitral valve replacement or plication is performed in selected cases in combination with myectomy, often with better hemodynamic results than those of myectomy alone. Mitral valve leaflet extension, in which a glutaraldehyde-preserved autologous pericardial patch is used to enlarge the mitral valve along its horizontal axis, is a novel surgical approach in patients with hypertrophic obstructive cardiomyopathy.

METHODS

Eight patients with hypertrophic obstructive cardiomyopathy were treated with mitral leaflet extension and myectomy. Preoperative and postoperative data (New York Heart Association functional class, number of drugs prescribed, width of the interventricular septum, severity of mitral valve regurgitation severity of systolic anterior motion of the mitral valve and outflow tract gradient) were compared with those of 12 patients undergoing myectomy alone.

RESULTS

Preoperative evaluation demonstrated that mitral regurgitation and systolic anterior motion of the mitral valve were more severe in the group undergoing mitral valve extension (p < 0.001 and p < 0.05, respectively). There were no deaths associated with either surgical procedure. Two patients, both treated by myectomy alone, died during the follow-up period. Postoperatively, patients treated with mitral valve extension had less mitral regurgitation (p < 0.005), less residual systolic anterior motion (p < 0.001), greater improvement in functional class (p = 0.05) and greater reduction in the number of drugs (p < 0.005) and in septal thickness (p < 0.05).

CONCLUSIONS

Mitral leaflet extension in combination with myectomy is a promising new surgical approach that may provide superior results to those of myectomy alone. Further studies are needed to determine the clinical value of this procedure.

Long-term clinical and echocardiographic follow-up after surgical correction of hypertrophic obstructive cardiomyopathy with extended myectomy and reconstruction of the subvalvular mitral apparatus

BACKGROUND

The standard surgical approach to hypertrophic obstructive cardiomyopathy (HOCM) was modified in the present series with a combination of extended myectomy with partial excision and mobilization of the papillary muscles.

METHODS AND RESULTS

Between 1979 and 1992, 58 patients (38 men and 20 women; mean age, 49 +/- 24 years) with HOCM were operated on with the use of this different technique. Their intraventricular gradients were 79 +/- 33 (+/- SD) mm Hg at rest and increased to 147 +/- 48 mm Hg with provocative maneuvers. Mild-to-moderate mitral regurgitation was present in 60% of the patients, and severe regurgitation was present in 5%. Ten patients required additional aortocoronary bypass graft surgery. Follow-up (mean, 84 months) was complete (100%). Hemodynamic improvement was documented by a significant (P < .01) decrease in left ventricular end-diastolic pressure from 19 +/- 9 to 14 +/- 6 mm Hg and reduction of basal outflow tract gradients to 5 +/- 7 mm Hg at rest and 16 +/- 24 mm Hg after provocation. Late mortality was 1.4% per patient-year, and no sudden cardiac deaths occurred during follow-up. Functional status was excellent for 84% of the patients; 8 patients were in New York Heart Association functional class III, and none were in class IV. Echocardiography revealed no outflow tract obstruction.

CONCLUSIONS

Extended myectomy and reconstruction of the subvalvular mitral apparatus in HOCM result in excellent functional improvement with relief of outflow tract obstruction. The technique can be performed safely despite its more aggressive surgical nature and allows an individualized strategy depending on the patient's extent and distribution of left ventricular hypertrophy.

Coexistence of mitral valve prolapse in a consecutive group of 528 patients with hypertrophic cardiomyopathy assessed with echocardiography

Hypertrophic cardiomyopathy and mitral valve prolapse are both conditions that may be genetically transmitted and incur a risk for sudden cardiac death. Although the small left ventricular cavity and distorted geometry characteristic of hypertrophic cardiomyopathy might suggest a predisposition to mitral valve prolapse, the frequency with which these two entities coexist and the potential clinical significance of such an association are not known. To further define the relation of hypertrophic cardiomyopathy and mitral valve prolapse, 528 consecutive patients with hypertrophic cardiomyopathy were studied by echocardiography. Patients ranged in age from 1 to 86 years (mean 45); 335 (63%) were male. Unequivocal echocardiographic evidence of systolic mitral valve prolapse into the left atrium was identified in only 16 (3%) of the 528 patients. The mitral valve excised at operation from three of the patients had morphologic characteristics of a floppy mitral valve, which was judged to be responsible for the echocardiographic findings. Occurrence of clinically evident atrial fibrillation was common in patients with hypertrophic cardiomyopathy and mitral valve prolapse (9 [56%] of 16). Hence, in a large group of patients with hypertrophic cardiomyopathy, the association of echocardiographically documented mitral valve prolapse was uncommon. The coexistence of mitral valve prolapse in patients with hypertrophic cardiomyopathy appears to predispose such patients to atrial fibrillation.

Impact of dual-chamber permanent pacing in patients with obstructive hypertrophic cardiomyopathy with symptoms refractory to verapamil and beta-adrenergic blocker therapy

BACKGROUND

Patients with obstructive hypertrophic cardiomyopathy (HCM) with symptoms refractory to drugs (beta-blockers or verapamil) are candidates for cardiac surgery (left ventricular septal myectomy or mitral valve replacement). The present study examines prospectively the ability of dual-chamber (DDD) pacing to improve symptoms and relieve left ventricular outflow obstruction in such patients.

METHODS AND RESULTS

Forty-four consecutive patients with obstructive HCM who had failed to benefit from pharmacotherapy underwent treadmill exercise tests, echocardiography, and cardiac catheterization before and 1.5-3 months after implantation of a DDD pacemaker. Symptoms (angina, dyspnea, palpitations, presyncope, and syncope), New York Heart Association functional class status (1.7 +/- 0.7 versus 3.4 +/- 0.5, p less than 0.00001), and exercise durations were improved at follow-up evaluation. This was associated with significant reduction in left ventricular outflow tract gradient (38 +/- 38 versus 87 +/- 43 mm Hg, p less than 0.0001) and significant increases in cardiac output and systemic arterial pressures. Notably, when pacing was discontinued and comparisons were made in sinus rhythm, treadmill exercise durations were greater and left ventricular outflow tract gradients were less at the follow-up evaluation compared with the baseline study.

CONCLUSIONS

DDD pacing is an effective alternative to surgery in most patients with obstructive HCM with drug-refractory symptoms. The beneficial effects of pacing continue to be evident when pacing is acutely discontinued.

Diversity of structural mitral valve alterations in hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is characterized by an asymmetrically hypertrophied left ventricle and is regarded as a disease of cardiac muscle.

METHODS AND RESULTS

To assess the possibility that the mitral valve itself may be involved in the disease process, we studied mitral valves from 94 patients with HCM and 45 normal control subjects. The area of the mitral leaflets was increased in patients with HCM compared with control subjects (12.9 +/- 3.7 versus 8.7 +/- 2.0 cm2; p less than 0.001). For the overall group of patients, this increase was largely caused by an increase in anterior leaflet length (2.2 +/- 0.5 cm for HCM versus 1.8 +/- 0.3 cm for control subjects; p less than 0.001), because circumference did not differ between the two groups. Mitral leaflet area was increased (greater than or equal to 12.0 cm2) in 55 (58%) of the 94 valves. In 12 of these 55 valves, both the anterior and posterior leaflets were enlarged; the other 43 valves had asymmetrical or segmental enlargement of either the anterior leaflet (36 patients) or a portion of posterior leaflet (seven patients). In addition, nine patients had a congenital malformation of the mitral apparatus in which one or both papillary muscles inserted directly into anterior mitral leaflet (mitral valve area was normal in seven of the nine).

CONCLUSIONS

Sixty-two (66%) of 94 mitral valves had a constellation of structural malformations, including increased leaflet area and elongation of the leaflets or anomalous papillary muscle insertion directly into anterior mitral leaflet. These findings expand the morphological definition of HCM by demonstrating that the disease process is not confined to cardiac muscle but rather many patients also have structural abnormalities of the mitral valve that are unlikely to be acquired or secondary to mechanical factors.

Severe mitral or aortic valve regurgitation, or both, requiring valve replacement for infective endocarditis complicating hypertrophic cardiomyopathy

Certain clinical and morphologic findings are described in 11 patients with hypertrophic cardiomyopathy complicated by infective endocarditis that produced severe mitral or aortic valve regurgitation, or both, necessitating valve replacement. All 11 patients had changes in the operatively excised valve or valves characteristic of healed infective endocarditis. The infection involved only the mitral valve in seven patients, only the aortic valve in three patients and both valves in one patient. Study of the operatively excised mitral valves indicated that the healed vegetations were located most commonly on the left ventricular aspects of the anterior mitral leaflet, indicating that vegetation had formed at contact points of this leaflet with mural endocardium of the left ventricular outflow tract. In all 11 patients, the infective endocarditis either worsened preexisting valve regurgitation or initiated valve regurgitation and led to worsened signs and symptoms of cardiac dysfunction, necessitating valve replacement. Functional class improved in the nine patients who survived 7 to 101 months after valve replacement. Hypertrophic cardiomyopathy appears to be a factor predisposing to infective endocarditis. Patients with hypertrophic cardiomyopathy should receive prophylactic antibiotic therapy during procedures that predispose to infective endocarditis.

Hypertrophic obstructive cardiomyopathy: ten- to 21-year follow-up after partial septal myectomy

This study reviews the outcome in 36 consecutive patients who survived partial septal myectomy for hypertrophic obstructive cardiomyopathy operated on between 1960 and 1972. All patients were followed up until death or until June 1981 (mean 13.4 years). Of the 26 survivors, 17 had been more than mildly symptomatic preoperatively, but only 1 remained so postoperatively. The operation was effective in relieving the obstruction (peak systolic pressure gradient reduced from 79 to 8 mm Hg [p less than 0.001]), and mitral regurgitation was relieved. No survivor's symptoms worsened, but 10 died late--4 suddenly, 5 from congestive heart failure, and 1 from a malignancy. The 10-year survival rate was 77%. No correlation with outcome was found with respect to age, surgical approach, preoperative functional class, pressure gradient, left ventricular end-diastolic pressure, or presence of atrial fibrillation, but atrial fibrillation occurring late postoperatively (12 patients) was associated with an increased frequency of late death (7 of 10 late deaths) or continuing New York Heart Association functional class III status. Early or late postoperative complete heart block occurred in 1 patient each. Thus, these results suggest a favorable effect of operation and support continued surgical intervention for appropriate patients.

Morphologic features of the normal and abnormal mitral valve

Anatomic and functional features of the normal and abnormal mitral valve are reviewed. Of 1,010 personally studied necropsy patients with severe (functional class III or IV, New York Heart Association) cardiac dysfunction from primary valvular heart disease, 434 (43%) had mitral stenosis (MS) with or without mitral regurgitation (MR): unassociated with aortic valve stenosis or regurgitation or with tricuspid valve stenosis in 189 (44%) patients, and associated with aortic stenosis in 152 (35%), with pure (no element of stenosis) aortic regurgitation in 65 (15%) patients, and with tricuspid valve stenosis with or without aortic valve stenosis in 28 (6%) patients. The origin of MS was rheumatic in all 434 patients. Of the 1,010 necropsy patients, 165 (16%) had pure MR (papillary muscle dysfunction excluded): unassociated with aortic valve stenosis or regurgitation or with tricuspid valve stenosis in 97 (59%) patients, and associated with pure aortic regurgitation in 45 (27%) and with aortic valve stenosis in 23 (14%) patients. When associated with dysfunction of the aortic valve, pure MR was usually rheumatic in origin, but when unassociated with aortic valve dysfunction it was usually nonrheumatic in origin. Review of operatively excised mitral valves in patients with pure MR unassociated with aortic valve dysfunction disclosed mitral valve prolapse (most likely an inherent congenital defect) as the most common cause of MR. Excluding the patients with MR from coronary heart disease (papillary muscle dysfunction), mitral prolapse was the cause of MR in 60 (88%) of the other 68 patients, and a rheumatic origin was responsible in only 3 of the 68 patients, all 68 of whom were greater than 30 years of age. Mitral anular calcification in persons aged greater than 65 years is usually associated with calcific deposits in the aortic valve cusps and in the coronary arteries. Because calcium in each of these 3 sites is common in older individuals residing in the Western World, it is most reasonable to view mitral anular calcification in older individuals as a manifestation of atherosclerosis. Mitral anular calcium appears to be extremely uncommon in persons with total serum cholesterol levels less than 150 mg/dl. Mitral anular calcium may produce mild MR and, if the deposits are heavy enough, MS.

Left ventricular myotomy. Physiologic approach to surgical therapy for IHSS

Twenty patients were operated on for idiopathic hypertrophic subaortic stenosis (IHSS) between 1966 and 1980. All were in New York Heart Association functional class 3 or 4, and 17 had overt congestive failure. The mean resting gradient across the left ventricular (LV) outflow tract preoperatively was 78 mm Hg. Seventeen patients underwent transaortic LV myotomy, one had mitral valve replacement (MVR), and two patients with rheumatic mitral insufficiency (MI) and IHSS underwent myotomy and MVR. There was one operative death (5 percent). Mean follow-up was 5.8 years. Eighteen of 19 survivors were improved to class 1 or 2. One patient whose gradient and symptoms were not relieved by myotomy was improved by myectomy and MVR. The MI was abolished or reduced by myotomy in ten of 13 patients. There were six late deaths, five of which are known or assumed to be cardiac related. We concluded that LV myotomy is a safe and effective technique for surgical management of IHSS. Left ventricular myectomy, MVR, or both are indicated in selected cases.

Noninvasive diagnosis of the cardiomyopathies

The presenting clinical features of the cardiomyopathies are nonspecific. Echocardiography is useful in detecting patients with cardiomyopathy and determining proper management. Echocardiography can be used to determine both cardiac structural measurements and cardiac function.

Operative treatment in hypertrophic subaortic stenosis. Techniques, and the results of pre and postoperative assessments in 83 patients

The results of operative treatment in 83 patients with idiopathic hypertrophic subaortic stenosis (IHSS) are described. Most patients with the disease are asymptomatic, or derive satisfactory symptomatic improvement from nonoperative therapy: administration of propranolol, exerice limitation, control of arrhythmia, etc. Operation is required, however, in 10-15% of patients, those who remain severely symptomatic after nonoperative treatment or who become refractory to it. Operation relieves symptoms in IHSS by relieving obstruction to left ventricular outflow, and for a patient to be considered an operative candidate severe obstruction must be documented at left heart catheterization either under resting conditions or after provocative interventions. All 83 patients were severely incapacitated--58 in Class III and 24 in Class IV. Seventy had obstruction at rest (average gradient 96 mm Hg), and 13 had only provocable obstruction. At operation the hypertrophic interventricular septum was exposed via an aortotomy, and a vertical bar of muscle was resected between parallel myotomy incisions. There were six operative deaths (7%); no patient has died since 1970. Seven patients have died late after operation, five of them from causes unrelated to their heart disease or the operation. All surviving patients describe symptomatic improvement. Fifty-two patients with obstruction at rest preoperatively (average gradient 95 mm Hg) have been studied postoperatively: no resting gradient was evident in 47, while in the remaining five the gradient was less than 25 mm Hg. Recurrence of obstruction has never been observed at late catheterization (21 pts) or late echocardiographic examination (37 pts). Obstruction could not be provoked postoperatively in ten of the 11 patients who had large gradients only with the Valsalva maneuver or isoproterenol administration preoperatively. Obstructed and provocable obstructed patients had similar symptomatic improvement after operation. A variety of rhythm and conduction abnormalities were observed both pre and postoperatively, and these are described in detail. The results of operation in these 83 patients with IHSS demonstrate that gratifying symptomatic and hemodynamic improvement uniformly follows left ventriculomyotomy and myectomy. Relief of obstruction and amelioration of symptoms have proved to be long-lasting during postoperative observation periods extending to 14 years. Continued application of the operative procedure in properly selected patients appears to be indicated.