Contemporary Surgical Management of Hypertrophic Cardiomyopathy.

More than half of symptomatic patients with hypertrophic cardiomyopathy (HCM) have left ventricular outflow tract (LVOT) obstruction. Septal reduction therapy by septal myectomy can dramatically relieve exertional dyspnea, chest pain, and presyncope in properly selected patients and is an important management pathway for many patients. The distribution and degree of hypertrophy in patients with obstructive HCM are variable and, as discussed in this review, can influence clinical manifestations of the disease and surgical management. Subaortic septal hypertrophy is the most common phenotype of obstructive HCM associated with LVOT obstruction, but midventricular obstruction and apical hypertrophy may occur in isolation or in conjunction with subaortic septal hypertrophy. In many comprehensive HCM centers, transaortic septal myectomy is the preferred method of septal reduction therapy for symptomatic patients with obstructive HCM. Early surgical approaches aimed at alleviating left LVOT obstruction were hampered by a lack of understanding of the anatomy and pathophysiology of obstructive HCM. With the advent of Doppler echocardiography and, more recently, cardiac magnetic resonance imaging, surgeons can precisely assess the location and degree of obstruction, left ventricular size and function, and morphology and function of the mitral valve. This review discusses the current understanding of the role of septal myectomy in the management of patients with HCM and details contemporary operative methods.

Optimizing Surgical Selection for Transposition With Left Ventricular Outflow Tract Obstruction.

BACKGROUND: Studies that have assessed the Rastelli and Nikaidoh operations for transposition of the great arteries (TGA) with obstructed left ventricular outflow tract obstruction (LVOTO) have not fully evaluated the anatomic drivers that may contribute to surgical selection. We present our procedural selection process for optimizing outcomes of complex TGA in the modern era. METHODS: This is a single-center, retrospective study that included pediatric patients who underwent either a Nikaidoh or Rastelli operation for the treatment of TGA-LVOTO, congenitally corrected TGA-LVOTO, or double-outlet right ventricle TGA type-LVOTO from June 2004 to June 2021. RESULTS: There were 34 patients stratified by Nikaidoh (n = 16) or Rastelli (n = 18) operation. The incidence of all postoperative complications and mortality was low, and the incidence of complications between the groups was similar. Patients were more likely to have undergone a Nikaidoh than a Rastelli if they had a pulmonary annulus >5 mm (87.5% vs 11.1%), anteriorly/posteriorly oriented great vessels (88% vs 8%), remote (80% vs 11%) or restrictive (75% vs 6%) ventricular septal defect, and right ventricular hypoplasia (50% vs 0%; all, P < .05). The resulting rates of reoperation were similar between the groups (44.0% vs 37.5%; P = .24) and largely composed of conduit replacements in the Rastelli patients and valvular repairs or replacements in the Nikaidoh group. Rates of catheter-based interventions were also similar. CONCLUSIONS: These findings suggest that for the optimal treatment of conotruncal anomalies with discordant ventriculoarterial connections, procedural selection should be based on pathoanatomic criteria that can ensure patients undergo the operation most suited to their anatomy.

Haemodynamic effects of acute intravenous landiolol in Takotsubo cardiomyopathy with dynamic left ventricular outflow tract obstruction.

Takotsubo cardiomyopathy (TCM) leads to serious left ventricular outflow tract (LVOT) obstruction with cardiogenic shock in 6%-20% of cases. The onset of LVOT obstruction, coupled with mitral regurgitation resulting from systolic anterior motion of mitral valve leaflets, can lead to haemodynamic instability in addition to severely impaired systolic function. We describe three patients who experienced chest discomfort following emotional stress. These patients displayed pronounced abnormalities on ECGs, insignificant obstructive coronary disease and haemodynamic instability due to LVOT obstruction. The infusion of landiolol, a short-acting beta blocker, was effective in releasing the gradient. Dynamic outflow obstruction is the major predictor of haemodynamic collapse. We suggested that an early identification of this complication in hypotensive patients with suspected TCM could be of utmost importance to optimise the therapeutic approach in the acute setting.

Accessory mitral valve tissue: a differential diagnosis of an obstructive mass on the left ventricular outflow tract.

Accessory mitral valve tissue is a rare congenital cardiac anomaly that is typically discovered incidentally during echocardiographic evaluation prompted by an asymptomatic murmur. This pathology has characteristic echocardiographic elements and is usually associated with other CHD. The decision to perform surgical resection depends on factors such as the degree of obstruction, presence of symptoms, presence of other CHDs, and risk of thrombosis. The researchers hereby present a case of an asymptomatic paediatric patient with accessory mitral valve tissue that produced left ventricular outflow tract obstruction.

Evaluation and implications of mitral regurgitation using cMRI in patients with hypertrophic cardiomyopathy.

OBJECTIVE: Mitral regurgitation (MR) represents an important feature in patients with hypertrophic cardiomyopathy (HCM) due to left ventricular outflow tract (LVOT) obstruction and mitral valve systolic anterior motion (SAM). Mitral valve anatomical variants associated with HCM also contribute to the severity of MR. The aim of this study is to evaluate MR severity and its correlation with different parameters in patients with HCM using cardiac magnetic resonance imaging (cMRI). PATIENTS AND METHODS: 130 patients with HCM underwent cMRI. Parameters assessed for the quantification of MR severity were mitral regurgitation volume (MRV) and mitral regurgitation fraction (MRF). cMRI was also used to characterize LV function, left atrium volume (LAV) index, filling pressures and structural abnormalities associated with HCM, all in correlation to MR. RESULTS: Patients with HCM had mild (26.9%), moderate (52.3%) or severe (20.7%) MR. Most relevant parameters related to MR severity were MRV and MRF; other parameters with strong correlation with MR were LAV index and E/E' ratio, both increasing with its severity. Patients with LVOT obstruction had more severe MR (70.3%), 79% of them due to SAM. LV ejection fraction (LVEF) increased proportionally with the severity of MR, while LV strain (LAS) was inversely correlated with it. Independent predictors for quantifying the severity of MR, after the adjustment for covariates, were MRV, MRF, SAM, LAV index and E/E'. CONCLUSIONS: cMRI can accurately assess MR in patients with HCM, especially by using novel indicators, MRV and MRF respectively, along with LAV index and E/E' ratio. Severe MR, due to SAM, is more frequent in the obstructive form of HCM (HOCM). Also, the severity of MR is significantly associated with significantly associated with MRV, MRF, LAV index and E/E' ratio.

TGA + IVS + LVOTO: patterns of practice and outcomes.

PURPOSE: Transposition of great arteries with intact ventricular septum and left ventricular outflow tract obstruction (TGA + IVS + LVOTO) is uncommon. We reviewed operations performed in patients with TGA + IVS + LVOTO in the European Congenital Heart Surgeons Association Congenital Database (ECHSA-CD). METHODS: All 109 patients with a diagnosis of TGA + IVS + LVOTO in ECHSA-CD who underwent cardiac surgery during a 21-year period (01/2000-02/2021, inclusive) were included. Preoperative variables, operative data, and postoperative outcomes were collected. RESULTS: These 109 patients underwent 176 operations, including 37 (21.0%) arterial switch operations (ASO), 26 (14.2%) modified Blalock-Taussig-Thomas shunts (MBTTS), 11 (6.2%) Rastelli operations, and 13 (7.3%) other palliative operations (8 superior cavopulmonary anastomosis[es], 4 Fontan, and 1 other palliative procedure). Of 37 patients undergoing ASO, 22 had a concomitant procedure.There were 68 (38.6%) reoperations, including 11 pacemaker procedures and 8 conduit operations. After a systemic-to-pulmonary artery shunt, reoperations included shunt reoperation (n = 4), Rastelli (n = 4), and superior cavopulmonary anastomosis (n = 3).Overall Operative Mortality was 8.2% (9 deaths), including three following ASO, two following "Nikaidoh, Kawashima, or LV-PA conduit" procedures, and two following Rastelli. Postoperative complications occurred after 36 operations (20.4%). The most common complications were delayed sternal closure (n = 11), postoperative respiratory insufficiency requiring mechanical ventilation >7 days (n = 9), and renal failure requiring temporary dialysis (n = 8). CONCLUSION: TGA + IVS + LVOTO is rare (109 patients in ECHSA-CD over 21 years). ASO, MBTTS, and Rastelli are the most common operations performed for TGA + IVS + LVOTO. Larger international studies with long-term follow-up are needed to better define the anatomy of the LVOTO and to determine the optimal surgical strategy.

Left ventricular anatomy in obstructive hypertrophic cardiomyopathy: beyond basal septal hypertrophy.

AIMS: Obstructive hypertrophic cardiomyopathy (oHCM) is characterized by dynamic obstruction of the left ventricular (LV) outflow tract (LVOT). Although this may be mediated by interplay between the hypertrophied septal wall, systolic anterior motion of the mitral valve, and papillary muscle abnormalities, the mechanistic role of LV shape is still not fully understood. This study sought to identify the LV end-diastolic morphology underpinning oHCM. METHODS AND RESULTS: Cardiovascular magnetic resonance images from 2398 HCM individuals were obtained as part of the NHLBI HCM Registry. Three-dimensional LV models were constructed and used, together with a principal component analysis, to build a statistical shape model capturing shape variations. A set of linear discriminant axes were built to define and quantify (Z-scores) the characteristic LV morphology associated with LVOT obstruction (LVOTO) under different physiological conditions and the relationship between LV phenotype and genotype. The LV remodelling pattern in oHCM consisted not only of basal septal hypertrophy but a combination with LV lengthening, apical dilatation, and LVOT inward remodelling. Salient differences were observed between obstructive cases at rest and stress. Genotype negative cases showed a tendency towards more obstructive phenotypes both at rest and stress. CONCLUSIONS: LV anatomy underpinning oHCM consists of basal septal hypertrophy, apical dilatation, LV lengthening, and LVOT inward remodelling. Differences between oHCM cases at rest and stress, as well as the relationship between LV phenotype and genotype, suggest different mechanisms for LVOTO. Proposed Z-scores render an opportunity of redefining management strategies based on the relationship between LV anatomy and LVOTO.

Aortic Atresia or Complex Left Outflow Tract Obstruction in the Presence of a Ventricular Septal Defect.

Severe left outflow tract obstruction (LVOTO) is not always associated with hypoplastic left heart syndrome (HLHS). Aortic valvar atresia or complex LVOTO in the presence of a large ventricular septal defect (VSD) are a rare group of lesions that offer the possibility of biventricular repair. The Yasui procedure is the commonest surgical approach which can be performed as a primary neonatal correction or as a staged procedure with a Norwood followed by a subsequent Rastelli. This article reviews the surgical outcomes and decision-making process. Both strategies are reasonable with the trend toward staged procedure in the setting of the additional interrupted arch, with neonatal survival of > 90% in the modern era and excellent long-term survival. Re-intervention is mostly related to conduit revision and the need for re-operation for LVOTO is rare. Deciding between conventional repair and the Yasui in cases of LVOTO/VSD can be difficult and there are no uniform accepted criteria. In a typical neonate, an aortic annulus < 4.5 mm is generally the limit of acceptability for a conventional repair. In selected cases of LVOTO/VSD, an alternative to the Yasui is the Ross-Konno. Retrospective comparisons between the 2 techniques are difficult due to differing patient characteristics (especially associated with mitral valve disease) but the neonatal Ross has been associated with higher early mortality.

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 novel negative inotropic drugs potentially useful for symptom management.

Opposing forces of cardiogenic shock: left ventricular outflow obstruction, severe mitral regurgitation, and left ventricular dysfunction in Takotsubo cardiomyopathy.

Rates of stress (Takotsubo) cardiomyopathy have increased during the coronavirus pandemic due to social stressors, even in patients who are not infected with the virus. At times, Takotsubo cardiomyopathy (TC) may present as cardiogenic shock. Herein, we present a case during the pandemic of shock from TC secondary to left ventricular outflow tract obstruction (LVOTO), mitral regurgitation (MR), and left ventricular (LV) dysfunction. The contrasting management strategy of LVOTO, MR, and LV failure was cause for clinical challenge, and we highlight the balance of treating these opposing forces.

Outcomes Over Follow-up ≥10 Years After Surgical Myectomy for Symptomatic Obstructive Hypertrophic Cardiomyopathy.

For over 50 years, surgical septal myectomy has been the preferred treatment for drug-refractory heart failure symptoms in obstructive hypertrophic cardiomyopathy (HCM). However, given the relatively youthful adult ages at which HCM surgery is usually performed, it is informative to evaluate longer-term results of myectomy after ≥10 years. We identified 139 consecutive obstructive HCM patients (50 ± 15 years of age; 55% men) who underwent surgical myectomy, 2003 to 2010 at Tufts HCM Center and followed 11.3 ± 2.7 years (range to 17). Operative mortality was low (0.6%) and left ventricular (LV) outflow gradients at rest were reduced from 56 ± 40 mm Hg preoperatively to 1 ± 7 mm Hg postoperatively, durable over the study period, with no patient requiring reoperation for the residual gradient. Over follow-up, 129 of 139 patients (93%) were alive ≥10 years after myectomy, including 17 patients ≥15 years. Of 118 patients with complete long-term clinical follow-up data, 109 (92%) experienced clinical improvement to New York Heart Association classes I or II. In 9 patients (8%) refractory class III/IV symptoms reoccurred 6.6 ± 3.9 years postoperatively, including 4 who ultimately underwent a heart transplant. After myectomy, there were 2 late HCM-related deaths, but none suddenly; notably 6 patients (12%) with prophylactic implantable cardioverter-defibrillators experienced appropriate therapy terminating ventricular tachycardia/ventricular fibrillation after myectomy. Survival following myectomy was 91% at 10 years (95% confidence interval: 85, 96%) not different from the age- and gender-matched general United States population (log-rank p = 0.64). In conclusion, myectomy provides permanent abolition of outflow gradients with reversal of heart failure and highly favorable long-term survival, representing a low-risk:high-benefit option when performed in experienced HCM centers. Myectomy did not protect absolutely against arrhythmic sudden death events, underscoring the importance of risk stratification in operative patients.

Surgical outcome of Yasui procedure for preserving biventricular function: single centre experience.

BACKGROUND: Yasui procedure is surgical repair intended to preserve biventricular function for patients with left ventricle outflow tract obstruction associated with aortic arch lesions and ventricular septal defect. METHODS: Retrospective chart review analysis of all patients who had Yasui procedure (2008-2020) comparing midterm outcome of one versus two stage repair. RESULTS: Twenty patients (70% female) underwent Yasui procedure in our center. Eight patients (40%) had left ventricle outflow tract obstruction /interrupted aortic arch, 7 patients (35%) had left ventricle outflow tract obstruction /coarctation of aorta, 3 patients (15%) had double outlet ventricle and ventricular septal defect that were unattainable for tunneling to one of the semilunar valves without creating obstruction, and 2 patients (10%) had aortic atresia with hypoplastic aortic arch. All patients had associated ventricular septal defect. Fifteen patients (75%) had one-stage repair and 5 patients (25%) had two-stage repair. Means age and weight for one and two-stage repair were 1.3 ± 2 months, 13.4 ± 11.5 months and 3.3 ± 0.6 kg, 7.8 ± 3.4 kg, respectively. During follow up, 8 patients (40%) required re- intervention, mainly for right ventricle-pulmonary artery conduit either dilation or replacement. The average duration of follow up was 5 years with nil mortality. CONCLUSION: Yasui procedure is effective approach for children who have left ventricle outflow tract obstruction associated with aortic arch anomalies and ventricular septal defect. Survival rate with single or staged repair is comparably good. During the first 5 year of follow up, nearly 40% of operated patients required re-intervention.

Impact of Body Mass Index on Outcome of Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy.

BACKGROUND: Obesity is highly prevalent in patients with obstructive hypertrophic cardiomyopathy (HCM). In this study, we investigated the impact of body mass index (BMI) in patients undergoing septal myectomy (SM) for obstructive HCM. METHODS: We reviewed 2746 patients who underwent transaortic SM for obstructive HCM from February 1993 through September 2018. Patients were stratified into 3 groups based on BMI (normal weight, <25 kg/m2; overweight, 25 to <30 kg/m2; and obese, ≥30 kg/m2). RESULTS: Preoperatively, the median left ventricular outflow tract gradient was 58 mm Hg, and there was no difference in gradients across BMI strata (P = .35). The percentage of obese patients with moderate or greater mitral valve regurgitation was lower (45.8%) compared with normal weight (52.9%) and overweight (55.4%) patients (P < .001). However, patients with a higher BMI were more likely to have New York Heart Association Functional Classification III/IV limitation at presentation (P < .001). After myectomy, anteroseptal thickness (P = .115) and left ventricular outflow tract gradient (P = .210) did not differ between groups. There were 14 (0.5%) deaths within 30 days postoperatively, and the risk was similar across BMI strata (P = .448). Model-estimated changes in average BMI at 10 years postprocedure showed stratum-specific increases ranging from 0.60 to 1.56 kg/m2. During a median follow-up of 7.2 years (interquartile range, 3.2-13.3 years), a higher BMI was associated with reduced survival after adjusting for baseline covariates (P = .001). CONCLUSIONS: SM is safe and effective in HCM patients with obesity, but the risk of late death increased with increasing BMI. Attention to risk factor management through weight loss may improve late results after SM.

Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy in the Elderly.

BACKGROUND: Hypertrophic obstructive cardiomyopathy is a genetic disorder treated with septal reduction therapy, either alcohol septal ablation or septal myectomy (SM). Historically older patients have been presumed to be poor candidates for SM and thus referred directly for alcohol septal ablation in some centers. We reviewed our experience with SM in older patients. METHODS: We identified 100 patients at our institution who underwent SM for hypertrophic obstructive cardiomyopathy from 2015 to 2020. Demographic and clinical characteristics and outcomes of patients 65 years or older were compared with patients younger than 65. RESULTS: Sixty-five patients were in the <65 group and 35 patients in the ≥65 group. Both groups had similar preoperative peak stress left ventricular outflow tract gradients (129 mm Hg vs 110 mm Hg, P < .001). Most patients in both groups had moderate to severe mitral regurgitation on preoperative stress echocardiography. The elderly group was more likely to have coronary artery bypass graft as a concomitant procedure (37% vs 8%, P < .001). Only 1 death occurred in the series secondary to a pulmonary embolism. At the 30-day follow-up on stress echocardiography, peak stress gradients were normal in both groups (21 and 20 mm Hg, respectively; P < .001), and 88% of all patients had trace to mild mitral regurgitation. CONCLUSIONS: Properly selected older patients can safely undergo SM with excellent outcomes similar to younger patients. Relief of left ventricular outflow tract obstruction and correction of mitral regurgitation are reliably achieved in both groups. Advanced age should not be a strict criteria for selecting septal reduction therapy approach.

A New Solution for Stenting Large Right Ventricular Outflow Tracts Before Transcatheter Pulmonary Valve Replacement.

BACKGROUND: Prestenting right ventricular outflow tracts (RVOTs) before transcatheter pulmonary valve replacement (TPVR) is essential. Optimus-XXL (AndraTec GmbH, Koblenz, Germany) is a new extra-large, balloon-expandable cobalt-chrome stent with promising technologies. METHODS: From June 2020 to November 2020, 15 patients with congenital heart disease, dysfunctional RVOTs and target TPVR diameter ≥ 23 mm received Optimus-XXL stents before proceeding to TPVR using the SAPIEN valve (Edwards Lifesciences, Irvine, CA). Standard safety and outcomes were prospectively assessed. RESULTS: Patients' median age and weight were 25.8 years (range: 10.5-63.1 years) and 58 kg (range: 43.8-101 kg), respectively. Underlying diagnosis was tetralogy of Fallot (66.7%), and RVOTs were patched (80%). Fifteen bare-metal stents were implanted using femoral (n = 14) and jugular approaches (n = 1). One conduit rupture was immediately controlled with a covered Optimus-XXL. Median stent length was 43 mm (range: 33-57 mm), and median target expansion diameter was 28 mm (range: 23-30 mm). Two procedural incidents occurred during stent delivery and were percutaneously treated. Stent stability was documented during TPVRs immediately performed in 14 patients. Median stent shortening was 13.7%, and median percentage of intended stent expansion was 95.9%. There was no stent fracture on the short-term follow-up (median: 4.5 months). CONCLUSIONS: We report the first implantations of Optimus-XXL stents in dysfunctional RVOTs with excellent preliminary results. Optimus-XXL should be considered as a valuable adjunct in the armamentarium for routine and complex TPVR procedures.

Dynamic left ventricular outflow tract obstruction in a patient with acute coronary syndrome and without the apical akinesia: Potential alternative mechanisms causing a dynamic left ventricular outflow tract obstruction other than a compensatory basal hyperkinesis.

The mechanism for dynamic left ventricular outflow tract obstruction (LVOTO) after acute coronary syndromes (ACS) is thought to be apical infarction with compensatory hyperkinesia of the residual normally perfused basal segments of the myocardium. However, herein, we report a patient with ACS and dynamic LVOTO (peak gradient of 250 mm Hg at rest) that could not be secondary to apical akinesia. We propose a potential alternative mechanism leading to dynamic LVOTO in ACS, namely, the interplay between sigmoid septum, basal hyperkinesis, and outflow tract narrowing induced by afterload reduction due to acute myocardial ischemia itself.

Takotsubo cardiomyopathy with LVOT obstruction in a case of STEMI: a rare cause of peri-PCI hypotension.

Takotsubo cardiomyopathy (TCM) associated with left ventricular outflow tract (LVOT) obstruction in the event of an ST-elevation myocardial infarction (STEMI) is a rare cause of hypotension during percutaneous coronary intervention (PCI). Herein, we describe a 57-year-old woman who presented with STEMI and underwent PCI. She developed hypotension which worsened during inotropic therapy. Echocardiography revealed evidence of LVOT obstruction in the setting of TCM. Therefore, inotropic support was promptly discontinued. Beta blockers and phenylephrine were rapidly administrated, resulting in improved blood pressure and stabilisation of the patient.