Surgery for Hypertrophic Obstructive Cardiomyopathy

Surface Morphology and Histopathological Aspects of Metallic Used Cardiovascular CoCr Stents

In this study, CoCr cardiovascular metallic stents with the same chemical composition as well as the adjacent tissues were analyzed. Recovered stents and adjacent tissues were characterized by surface morphology techniques like light microscopy (LM), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). The presence of metals in the tissue from around explanted stent was also confirmed by TEM method. The released metal ions were measured using inductively coupled plasma mass spectrometry (ICP-MS). Histopathological analysis was used to highlight host tissue response to the implanted stents. EDX analysis revealed that 21 stents had the same composition. The quantities of Cr ions detected in the tissues were between 5 and 14 ppb and for Co ions were between 4 and 10 ppb. The tissue sections near the layers that generated large quantities of ions showed restenosis development and the deposits of surface calcifications were highlighted. The heavy metal levels observed in this study due to corrosion are too low to cause a systemic toxic response.

Hypertrophic Cardiomyopathy and Left Ventricular Outflow Tract Obstruction: Expecting the Unexpected

Hypertrophic cardiomyopathy is an increasingly recognized clinical disease that carries perioperative risk. Patients may or may not carry a preoperative diagnosis, but provocable left ventricular outflow tract gradients place them at risk for hemodynamic compromise under surgical conditions. Early recognition of obstructive patterns and rapid management alterations in the face of instability are imperative for the treatment of these patients. This review focuses on the diagnostic criteria, risk factors, and management strategies for the perioperative hypertrophic cardiomyopathy patient. Finally, novel diagnostic modalities are discussed.

Quantitative assessment of damage during MCET: a parametric study in a rodent model

Background

Myocardial cavitation-enabled therapy (MCET) has been proposed as a means to achieve minimally invasive myocardial reduction using ultrasound to produce scattered microlesions by cavitating contrast agent microbubbles.

Methods

Rats were treated using burst mode focused ultrasound at 1.5 MHz center frequency and varying envelope and pressure amplitudes. Evans blue staining indicated lethal cardiomyocytic injury. A previously developed quantitative scheme, evaluating the histologic treatment results, provides an insightful analysis for MCET treatment parameters. Such include ultrasound exposure amplitude and pulse modulation, contrast agent dose, and infusion rate.

Results

The quantitative method overcomes the limitation of visual scoring and works for a large dynamic range of treatment impact. Macrolesions are generated as an accumulation of probability driven microlesion formations. Macrolesions grow radially with radii from 0.1 to 1.6 mm as the ultrasound exposure amplitude (peak negative) increases from 2 to 4 MPa. To shorten treatment time, a swept beam was investigated and found to generate an acceptable macrolesion volume of about 40 μL for a single beam position.

Conclusions

Ultrasound parameters and administration of microbubbles directly influence lesion characteristics such as microlesion density and macrolesion dimension. For lesion generation planning, control of MCET is crucial, especially when targeting larger pre-clinical models.

Controversies in cardiovascular medicine. Benefits of surgery in obstructive hypertrophic cardiomyopathy: bring septal myectomy back for European patients

Hypertrophic cardiomyopathy (HCM), a heterogeneous genetic heart disease with global distribution, is an important cause of heart failure disability at any age. For 50 years, surgical septal myectomy has been the preferred and primary treatment strategy for most HCM patients with progressive, drug refractory functional limitation due to left ventricular (LV) outflow tract obstruction. With very low surgical mortality at experienced centres, septal myectomy reliably abolishes impedance to LV outflow and heart failure-related symptoms, restores quality of life, and importantly is associated with long-term survival similar to that in the general population. Nevertheless, alternatives to surgical management are necessary for selected HCM patients. For example, after a brief flirtation with dual-chamber pacing 20 years ago, percutaneous alcohol septal ablation has garnered a large measure of enthusiasm and a dedicated following in the interventional cardiology community, achieving benefits for patients, paradoxically, by virtue of producing a transmural myocardial infarct. However, an unintended consequence has been the virtual obliteration of the surgical option for HCM patients in Europe, where several robust myectomy programmes once existed. Therefore, clear differences are now evident internationally regarding management strategies for symptomatic obstructive HCM. The surgical option is now unavailable to many patients based solely on geography, including some who would likely benefit more substantially from surgical myectomy than from catheter-based alcohol ablation. It is our aspiration that this discussion will generate reconsideration and resurgence of interest in surgical septal myectomy as a treatment option for severely symptomatic obstructive HCM patients within Europe.

A decade of percutaneous septal ablation in hypertrophic cardiomyopathy

Percutaneous septal ablation has emerged as a less invasive treatment of symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM). In the past decade, the availability of this sophisticated technique has revived the interest of cardiologists in left ventricular outflow tract obstruction, which led to the recognition that most patients with HCM have the obstructive type. Follow-up studies have already shown the safety and efficacy of the procedure, which offers symptomatic relief in most patients. Long-term survival is comparable to historical reports after surgical myectomy. Complications are rare and can be further reduced with increased experience of the operators, and the theoretical concern for possible ventricular arrhythmogenicity of the myocardial scar has not been documented by the existing data. Although there are still no randomized trials, percutaneous septal ablation is undeniably a viable alternative for patients with HOCM.

Outcome of alcohol septal ablation for obstructive hypertrophic cardiomyopathy

BACKGROUND

The clinical efficacy of alcohol septal ablation for drug-refractory hypertrophic cardiomyopathy remains unclear. This study examines the outcome of alcohol septal ablation performed at a tertiary hypertrophic cardiomyopathy referral center.

METHODS AND RESULTS

Among 601 patients with severely symptomatic obstructive hypertrophic cardiomyopathy referred for alcohol septal ablation or myectomy from 1998 to 2006, 138 patients (median age, 64 years; 39% men) chose to undergo ablation. Procedural complications included death in 1.4%, sustained ventricular arrhythmias in 3%, tamponade in 3%, and pacemaker implantation in 20%. This rate was higher than a combined complication rate of 5% in age- and gender-matched patients who had undergone septal myectomy at Mayo Clinic (P<0.0001). Four-year survival free of all mortality was 88.0% (95% confidence interval, 79.4 to 97.5%), which was similar to that of the age- and gender-matched patients who had undergone myectomy (P=0.18). Six patients had documented ventricular arrhythmias after ablation, 4 of whom had successful intervention. Four-year survival free of death and severe New York Heart Association class III/IV symptoms after septal ablation was 76.4%, and 71 patients (51%) became asymptomatic. Myectomy patients <or=65 years of age had significantly better survival free of death and severe symptoms (P=0.01).

CONCLUSIONS

Alcohol septal ablation is an efficacious procedure if performed in an experienced institution and may resolve symptoms in a subset of patients with obstructive hypertrophic cardiomyopathy. However, the procedural complication rate exceeds that of myectomy. Patients 65 years of age have better symptom resolution with myectomy. No impairment in short-term survival was noted in this nonrandomized study, but the long-term outcome remains unknown.

Depression, anxiety, and quality of life in patients with obstructive hypertrophic cardiomyopathy three months after alcohol septal ablation

Patients with obstructive hypertrophic cardiomyopathy are presumed to have poor quality of life (QOL) and distress related to their cardiac symptoms and functional limitations. Alcohol septal ablation (ASA) is designed to improve heart function and reduce cardiac symptoms. The purpose of this study was to examine psychosocial factors and QOL in patients with obstructive hypertrophic cardiomyopathy before and 3 months after ASA. Twenty-two adult participants (mean age 57 +/- 14 years, 59% women, 100% Caucasian, 67% married) were recruited during their initial evaluations or scheduled index hospitalizations for ASA. Psychosocial and medical measures were collected before and 3 months after ASA. The results indicated that before ASA, 57% of patients reported clinically relevant levels of depression (Center for Epidemiologic Studies Depression Scale score >16), symptoms of anxiety, and reduced QOL. Repeated-measures analyses of variance revealed that ASA is an effective procedure in reducing disease severity (i.e., peak left ventricular outflow tract gradient, septal thickness, posterior wall thickness) (p = 0.001 to 0.05), depression (p = 0.005), and anxiety (p = 0.029) and improving cardiac-specific QOL (p < 0.001) and generic physical health-related QOL (p = 0.009). Changes in satisfaction with life, optimism, and generic mental health-related QOL were not significant (p = 0.143 to 0.899). In conclusion, significant psychological distress and compromised well-being were present in this sample of pre-ASA patients with obstructive hypertrophic cardiomyopathy. After ASA, significant reductions in psychological distress and improvements in well-being and echocardiographic parameters indicating disease severity were demonstrated. These results suggest that patients perceived broad health benefits from ASA in short-term follow-up.

Surgical Myectomy Versus Alcohol Septal Ablation for Obstructive Hypertrophic Cardiomyopathy

Dynamic left ventricular outflow tract obstruction is an important pathophysiologic feature of hypertrophic cardiomyopathy (HCM) and a predictor of clinical deterioration and cardiovascular mortality. Patients with marked obstruction and severe limiting symptoms refractory to maximum medical management are considered candidates for invasive septal reduction therapy, which includes surgical myectomy and alcohol septal ablation (ASA). Availability of both surgical myectomy and ASA has polarized the cardiovascular community concerning the most appropriate implementation of these two interventions. The ensuing controversy of whether myectomy and ASA are truly equivalent options has resulted in calls for a prospective randomized trial. However, upon analysis, such a myectomy versus ASA trial, adequately powered to compare the key issue of long-term outcome, poses a myriad of practical problems that seem virtually insurmountable. Therefore, it is appropriate to revisit this evolving debate at this time, identify the unique obstacles to a randomized study design, and achieve some clarity concerning the most realistic clinical strategies for symptomatic patients with HCM and outflow obstruction.

Comparison of Surgical Septal Myectomy and Alcohol Septal Ablation With Cardiac Magnetic Resonance Imaging in Patients With Hypertrophic Obstructive Cardiomyopathy

OBJECTIVES

This study sought to describe the acute morphologic differences that result from septal myectomy and alcohol septal ablation using cardiac magnetic resonance (CMR) imaging.

BACKGROUND

Surgical septal myectomy and alcohol septal ablation relieve left ventricular outflow tract obstruction in severely symptomatic patients with hypertrophic cardiomyopathy (HCM).

METHODS

Cine and contrast-enhanced CMR images were obtained in HCM patients before and after septal myectomy (n = 24) and alcohol septal ablation (n = 24). Location of septal reduction, extent of myocardial necrosis, and conduction system abnormalities with each technique were compared.

RESULTS

With septal myectomy, there was a discrete area of resected tissue consistently localized to anterior septum. In contrast, alcohol septal ablation resulted in a more variable effect. In most patients, alcohol septal ablation caused a transmural region of tissue necrosis, located more inferiorly in the basal septum than myectomy and usually extending into the right ventricular side of the septum at the midventricular level. However, there were 6 patients after alcohol septal ablation in whom there was sparing of the basal septum with residual gradients at follow-up. After the procedure, left bundle branch block developed in 46% of septal myectomy patients, and right bundle branch block was evident in 58% of alcohol septal ablation patients.

CONCLUSIONS

Septal myectomy and alcohol septal ablation for severely symptomatic, drug-refractory patients with obstructive HCM have different morphologic effects and location sites on left ventricular septal myocardium. Septal myectomy provides consistent resection of the obstructing portion of the anterior basal septum, whereas the effect of ethanol septal ablation is more variable. These findings may have important implications for patient selection and management as well as long-term outcome.

Impact of Ethanol Dosing on the Long-Term Outcome of Alcohol Septal Ablation for Obstructive Hypertrophic Cardiomyopathy A Single-Center, Prospective, and Randomized Study

BACKGROUND

The impact of ethanol dose on the long-term outcome of alcohol septal ablation (ASA) for obstructive hypertrophic cardiomyopathy was investigated.

METHODS AND RESULTS

Fifty-four patients (age 24-82 years; 65% women) undergoing ASA were randomized into 2 groups according to the dose of injected ethanol: Group A 1-2 ml, Group B >2 ml. Clinical and echocardiographic data were obtained at baseline and during follow-up. The volume of ethanol injected was 1.50+/-0.4 and 2.60+/-0.6 ml (p<0.001) with a subsequent peak of creatine kinase-MB of 2.25+/-1.00 and 2.62+/-1.57 microkat/L (p=0.02) in Groups A and B, respectively. The median follow-up was 39 (range 6-72) months after ASA, during which 1 patient died and 1 repeat procedure was necessary in both groups of patients. Both groups had a significant and similar improvement in outflow pressure gradient, dyspnea (New York Heart Association functional class) and angina pectoris (Canadian Cardiovascular Society class) (p<0.001). There was a significant decrease in the left ventricular ejection fraction (LVEF) in Group B (81+/-7 vs 75+/-7%; p=0.002), but not in Group A (80+/-7 vs 79+/-7%; p=0.67). Thinning of the basal septum was more pronounced in Group B than in Group A (9.3+/-5.7 vs 6.6+/-3.4 mm; p=0.04).

CONCLUSIONS

A lower dose of ethanol injected into the target septal branch reduces both the size of necrosis and subsequent thinning of the basal septum, and preserves LVEF during long-term follow-up. Moreover, the low dose (1-2 ml) is as safe and as hemodynamically efficacious as higher doses.