Mitral Leaflet Shortening as an Ancillary Procedure in Obstructive Hypertrophic Cardiomyopathy.

BACKGROUND: Mitral leaflet elongation is common in hypertrophic cardiomyopathy (HCM), contributes to obstructive physiology, and presents a challenge to the dual surgical goals of abolition of outflow gradients and abolition of mitral regurgitation. Anterior leaflet shortening, performed as an ancillary surgical procedure during myectomy, is controversial. METHODS: This was a retrospective study of all patients undergoing myectomy from January 2010 to March 2020, with analysis of survival and echocardiographic results. The study compared outcomes of patients treated with myectomy and concomitant mitral leaflet shortening with patients treated with myectomy alone. Over this time, the technique for mitral shortening evolved from anterior leaflet plication to residual leaflet excision (ReLex). RESULTS: Myectomy was performed in 416 patients aged 57.5 ± 13.6 years, and 204 (49%) patients were female. Average follow-up was 5.4 ± 2.8 years. Survival follow-up was complete in 415 patients. Myectomy without valve replacement was performed in 332 patients, of whom 192 had mitral valve shortening (58%). Mitral leaflet plication was performed in 73 patients, ReLex in 151, and both procedures in 32. Hospital mortality for patients undergoing myectomy was 0.7%. At 8 years, cumulative survival was 95% for both the myectomy combined with leaflet shortening group and the myectomy alone group, with no difference in survival between the 2 groups. There was no difference in survival between the anterior leaflet plication and ReLex groups. Echocardiography 2.5 years after surgery showed a decrease in resting and provoked gradients, mitral regurgitation, and left atrial volume and no difference in key variables between patients who underwent ancillary leaflet shortening and patients who underwent myectomy alone. CONCLUSIONS: These results affirm that mitral shortening may be an appropriate surgical judgment for selected patients.

Routine Extubation in the Operating Room After Isolated Coronary Artery Bypass.

BACKGROUND: The benefits of fast-track extubation in the intensive care unit (ICU) after cardiac surgery are well established. Although extubation in the operating room (OR) is safe in carefully selected patients, widespread use of this strategy in cardiac surgery remains unproven. This study was designed to evaluate perioperative outcomes with OR vs ICU extubation in patients undergoing nonemergency, isolated coronary artery bypass grafting (CABG). METHODS: The Society of Thoracic Surgeons (STS) data for all single-center patients who underwent nonemergency isolated CABG over a 6-year interval were analyzed. Perioperative morbidity and mortality with ICU vs OR extubation were compared. RESULTS: Between January 1, 2017 and December 31, 2022, 1397 patients underwent nonemergency, isolated CABG; 891 (63.8%) of these patients were extubated in the ICU, and 506 (36.2%) were extubated in the OR. Propensity matching resulted in 414 pairs. In the propensity-matched cohort, there were no differences between the 2 groups in incidence of reintubation, reoperation for bleeding, total operative time, stroke or transient ischemic attack, renal failure, or 30-day mortality. OR-extubated patients had shorter ICU hours (14 hours vs 20 hours; P < .0001), shorter postoperative hospital length of stay (3 days vs 5 days; P < .0001), a greater likelihood of being discharged directly to home (97.3% vs 89.9%; P < .0001), and a lower 30-day readmission rate (1.7% vs 4.1%; P = .04). CONCLUSIONS: Routine extubation in the OR is a feasible and safe strategy for a broad spectrum of patients after nonemergency CABG, with no increase in perioperative morbidity or mortality. Wider adoption of routine OR extubation for nonemergency CABG is indicated.

Histopathology of the Mitral Valve Residual Leaflet in Obstructive Hypertrophic Cardiomyopathy.

BACKGROUND: Mitral valve (MV) elongation is a primary hypertrophic cardiomyopathy (HCM) phenotype and contributes to obstruction. The residual MV leaflet that protrudes past the coaptation point is especially susceptible to flow-drag and systolic anterior motion. Histopathological features of MVs in obstructive hypertrophic cardiomyopathy (OHCM), and of residual leaflets specifically, are unknown. OBJECTIVES: The purpose of this study was to characterize gross, structural, and cellular histopathologic features of MV residual leaflets in OHCM. On a cellular-level, we assessed for developmental dysregulation of epicardium-derived cell (EPDC) differentiation, adaptive endocardial-to-mesenchymal transition and valvular interstitial cell proliferation, and genetically-driven persistence of cardiomyocytes in the valve. METHODS: Structural and immunohistochemical staining were performed on 22 residual leaflets excised as ancillary procedures during myectomy, and compared with 11 control leaflets from deceased patients with normal hearts. Structural components were assessed with hematoxylin and eosin, trichrome, and elastic stains. We stained for EPDCs, EPDC paracrine signaling, valvular interstitial cells, endocardial-to-mesenchymal transition, and cardiomyocytes. RESULTS: The residual leaflet was always at A2 segment and attached by slack, elongated and curlicued, myxoid chords. MV residual leaflets in OHCM were structurally disorganized, with expanded spongiosa and increased, fragmented elastic fibers compared with control leading edges. The internal collagenous fibrosa was attenuated and there was collagenous tissue overlying valve surfaces in HCM, with an overall trend toward decreased leaflet thickness (1.09 vs 1.47 mm, P = 0.08). No markers of primary cellular processes were identified. CONCLUSIONS: MV residual leaflets in HCM were characterized by histologic findings that were likely secondary to chronic hemodynamic stress and may further increase susceptibility to systolic anterior motion.

Low-Dose vs Standard Warfarin After Mechanical Mitral Valve Replacement: A Randomized Trial.

BACKGROUND: Current guidelines recommend a target international normalized ratio (INR) range of 2.5 to 3.5 in patients with a mechanical mitral prosthesis. The Prospective Randomized On-X Anticoagulation Clinical Trial (PROACT) Mitral randomized controlled noninferiority trial assessed safety and efficacy of warfarin at doses lower than currently recommended in patients with an On-X (Artivion, Inc) mechanical mitral valve. METHODS: After On-X mechanical mitral valve replacement, followed by at least 3 months of standard anticoagulation, 401 patients at 44 North American centers were randomized to low-dose warfarin (target INR, 2.0-2.5) or standard-dose warfarin (target INR, 2.5-3.5). All patients were prescribed aspirin, 81 mg daily, and encouraged to use home INR testing. The primary end point was the sum of the linearized rates of thromboembolism, valve thrombosis, and bleeding events. The design was based on an expected 7.3% event rate and 1.5% noninferiority margin. RESULTS: Mean patient follow-up was 4.1 years. Mean INR was 2.47 and 2.92 (P <.001) in the low-dose and standard-dose warfarin groups, respectively. Primary end point rates were 11.9% per patient-year in the low-dose group and 12.0% per patient-year in the standard-dose group (difference, -0.07%; 95% CI, -3.40% to 3.26%). The CI >1.5%, thus noninferiority was not achieved. Rates (percentage per patient-year) of the individual components of the primary end point were 2.3% vs 2.5% for thromboembolism, 0.5% vs 0.5% for valve thrombosis, and 9.13% vs 9.04% for bleeding. CONCLUSIONS: Compared with standard-dose warfarin, low-dose warfarin did not achieve noninferiority for the composite primary end point. (PROACT Clinicaltrials.gov number, NCT00291525).

WITHDRAWN: Low-Dose Versus Standard Warfarin After Mechanical Mitral Valve Replacement: A Randomized Controlled Trial.

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Mitral annular calcification in hypertrophic cardiomyopathy.

BACKGROUND: Changes in mitral valve anatomy contribute to left ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM). Mitral annular calcification (MAC) is common among patients with HCM but its implications are currently unknown. METHODS: We tested the hypothesis that echocardiographic MAC would be associated with anterior displacement of the mitral valve and LVOTO in a cohort of 304 patients with HCM aged ≥ 60 years (mean [SD] age 71.6 [7.7] years, 52% women). RESULTS: MAC was present in 141 (46%) patients. The mean (SD) MAC offset distance was 9.8 (4.8) mm. A higher proportion of those with MAC compared to those without MAC had SAM (84.2 vs. 63.8%, p < 0.001) and LVOTO (80.9 vs. 57.9%, p < 0.001). In patients with MAC, the septal-mitral valve distance was shorter compared to those without (19.4 [4.0] vs 21.5 [4.9] mm, p < 0.001). The mitral valve position ratio was greater in those with MAC compared to those without (1.00 [0.79, 1.22] vs. 0.86 [0.67, 1.05], p < 0.001) denoting greater anterior displacement, especially in those with MAC and LVOTO. After multivariable adjustment, MAC offset distance was associated with LVOTO (OR 1.16 [95% CI 1.07, 1.28] per mm, p = 0.001). Over a median follow-up of 2.7 years, 42 (29.8%) patients with MAC underwent surgery to relieve LVOTO, with no deaths. CONCLUSION: This study adds MAC to the known geometrical alterations of the mitral valve that predispose to LVOTO and suggests that surgical relief of LVOTO in the presence of MAC is safe when performed by an experienced surgeon.

Cardiac AA amyloidosis in a patient with obstructive hypertrophic cardiomyopathy.

Cardiac amyloid A (AA) amyloidosis is rare. We present the case of a 72-year-old woman with obstructive hypertrophic cardiomyopathy (HCM) and biopsy-proven renal AA amyloidosis whose dyspnea and exercise intolerance had worsened over the previous year. Her AA amyloidosis was suspected to be secondary to chronic diverticulitis for which she had undergone hemicolectomy and sigmoidectomy 3 years prior. Echocardiographic findings were consistent with worsening left ventricular outflow tract obstruction at rest. Cardiac magnetic resonance imaging revealed patchy areas of midwall late gadolinium enhancement. Right ventricular endomyocardial biopsy did not reveal amyloid deposition, and cardiac technetium-99m pyrophosphate scintigraphy did not suggest transthyretin amyloidosis. The patient underwent septal myectomy with resection of an accessory papillary muscle. Pathological examination of the myectomy specimen was consistent with HCM. In addition, there was a thick layer of diffuse endocardial and vascular amyloid deposition that was identified as AA type by laser-microdissection with liquid chromatography-coupled tandem-mass spectrometry. This case report highlights the presence of 2 distinct disease processes occurring simultaneously and the importance of tissue diagnosis of AA amyloidosis, a condition that is not commonly associated with HCM.

Hypertrophic cardiomyopathy with dynamic obstruction and high left ventricular outflow gradients associated with paradoxical apical ballooning.

BACKGROUND: Acute left ventricular (LV) apical ballooning with normal coronary angiography occurs rarely in obstructive hypertrophic cardiomyopathy (OHCM); it may be associated with severe hemodynamic instability. METHODS, RESULTS: We searched for acute LV ballooning with apical hypokinesia/akinesia in databases of two HCM treatment programs. Diagnosis of OHCM was made by conventional criteria of LV hypertrophy in the absence of a clinical cause for hypertrophy and mitral-septal contact. Among 1519 patients, we observed acute LV ballooning in 13 (0.9%), associated with dynamic left ventricular outflow tract (LVOT) obstruction and high gradients, 92 ± 37 mm Hg, 10 female (77%), age 64 ± 7 years, LVEF 31.6 ± 10%. Septal hypertrophy was mild compared to that of the rest of our HCM cohort, 15 vs 20 mm (P < 0.00001). An elongated anterior mitral leaflet or anteriorly displaced papillary muscles occurred in 77%. Course was complicated by cardiogenic shock and heart failure in 5, and refractory heart failure in 1. High-dose beta-blockade was the mainstay of therapy. Three patients required urgent surgical relief of LVOT obstruction, 2 for refractory cardiogenic shock, and one for refractory heart failure. In the three patients, surgery immediately normalized refractory severe LV dysfunction, and immediately reversed cardiogenic shock and heart failure. All have normal LV systolic function at 45-month follow-up, and all have survived. CONCLUSIONS: Acute LV apical ballooning, associated with high dynamic LVOT gradients, may punctuate the course of obstructive HCM. The syndrome is important to recognize on echocardiography because it may be associated with profound reversible LV decompensation.

Intraoperative Two- and Three-Dimensional Transesophageal Echocardiography in Combined Myectomy-Mitral Operations for Hypertrophic Cardiomyopathy.

Transesophageal echocardiography is essential in guiding the surgical approach for patients with obstructive hypertrophic cardiomyopathy. Septal hypertrophy, elongated mitral valve leaflets, and abnormalities of the subvalvular apparatus are prominent features, all of which may contribute to left ventricular outflow tract obstruction. Surgery aims to alleviate the obstruction via an extended myectomy, often with an intervention on the mitral valve and subvalvular apparatus. The goal of intraoperative echocardiography is to assess the anatomic pathology and pathophysiology in order to achieve a safe intraoperative course and a successful repair. This guide summarizes the systematic evaluation of these patients to determine the best surgical plan.

Coronary Artery Bypass Graft Surgery Using the Radial Artery, Right Internal Thoracic Artery, or Saphenous Vein as the Second Conduit.

BACKGROUND: It is not clear whether radial artery (RA), right internal thoracic artery (RITA), or saphenous vein (SV) is the preferred second bypass graft during coronary artery bypass graft surgery using the left internal thoracic artery (LITA) in patients aged less or greater than 70 years. METHODS: Late survival data were collected for 13,324 consecutive, isolated, primary coronary artery bypass graft surgery patients from three hospitals. Cox regression analysis was performed on all patients grouped by age. RESULTS: Adjusted Cox regression showed overall better RA versus SV survival (hazard ratio [HR] 0.82, p < 0.001) and no difference in RITA versus SV survival (HR 0.95, p = 0.35). However, the survival benefit of RA versus SV was seen only in patients aged less than 70 years (HR 0.77, p < 0.001); and RITA patients aged less than 70 years also had a survival benefit compared with SV (HR 0.86, p = 0.03). There was no difference in survival for RA versus RITA across all ages. CONCLUSIONS: For patients aged less than 70 years, the optimal grafting strategy is using either RA or RITA as the second preferred graft. In patients aged 70 years or more, RA and RITA grafting should be used selectively. Multiple arterial grafting using either RA or RITA should be more widely utilized during coronary artery bypass graft surgery for patients less than 70 years of age.

The Mitral Valve in Obstructive Hypertrophic Cardiomyopathy: A Test in Context.

Mitral valve abnormalities were not part of modern pathological and clinical descriptions of hypertrophic cardiomyopathy in the 1950s, which focused on left ventricular (LV) hypertrophy and myocyte fiber disarray. Although systolic anterior motion (SAM) of the mitral valve was discovered as the cause of LV outflow tract obstruction in the M-mode echocardiography era, in the 1990s structural abnormalities of the mitral valve became appreciated as contributing to SAM pathophysiology. Hypertrophic cardiomyopathy mitral malformations have been identified at all levels. They occur in the leaflets, usually elongating them, and also in the submitral apparatus, with a wide array of malformations of the papillary muscles and chordae, that can be detected by transthoracic and transesophageal echocardiography and by cardiac magnetic resonance. Because they participate fundamentally in the predisposition to SAM, they have increasingly been repaired surgically. This review critically assesses imaging and measurement of mitral abnormalities and discusses their surgical relief.

Echocardiography before and after resect-plicate-release surgical myectomy for obstructive hypertrophic cardiomyopathy.

BACKGROUND: Anatomic features of obstructive hypertrophic cardiomyopathy are septal hypertrophy, elongated mitral leaflets, and anterior displacement of the papillary muscles. In addition to extended myectomy, the resect-plicate-release operation adds horizontal plication of the anterior mitral leaflet (AML) and release of the anterolateral papillary muscle (APM) in selected patients. The aim of this study was to test the hypotheses that (1) preoperative findings would be associated with procedures applied, (2) anatomic corrections would be observable postoperatively, and (3) there would be consistently good physiologic outcomes. METHODS: A retrospective study was conducted of patients with obstructive hypertrophic cardiomyopathy who had adequate echocardiograms before and 9.5 ± 12 months after the resect-plicate-release operation was performed from 2006 to 2012. RESULTS: Seventy-seven patients underwent myectomy, 50 AML plication, and 50 APM release. Patients who underwent plication had longer AMLs (32 ± 4 vs 28 ± 4 mm; P < .004). Anterior extension of the APM was more common with papillary muscle release (86% vs 62%, P < .04). Twenty-seven (35%) had septal thickness ≤ 18 mm; mitral valve-sparing operations were possible because of plication in 19 patients (70%), papillary release in 21 (78%), and one or both in 96%. Patients who underwent plication had decreased AML length by 16%, residual leaflet length by 33%, and protrusion by 24%. After APM release, there was decreased distance from mitral coaptation to the posterior wall. Surgery abolished severe systolic anterior motion and resting gradients and reduced mitral regurgitation. CONCLUSIONS: Echocardiographic AML length and directly observed slack provides a basis to recommend performance of plication and define its extent; plication decreases AML protrusion and stiffens the leaflet. Anterior APM recommends release, which drops the coaptation point posteriorly. Systematic relief of all aspects of obstructive pathophysiology results in consistent outcomes.

Optimal conduit for diabetic patients: propensity analysis of radial and right internal thoracic arteries.

BACKGROUND: Multiple arterial grafts, in addition to the left internal thoracic artery, improve long-term survival after coronary artery bypass grafting (CABG); yet, the use of this procedure remains low for both the right internal thoracic artery (RITA) and the radial artery (RA). To identify the optimal arterial conduit to deploy for revascularization of diabetic patients, we compared the outcomes for RA and RITA grafts to the circumflex coronary. METHODS: From January 1, 1995, to December 31, 2011, 908 consecutive diabetic patients underwent first-time, isolated CABG (99% on-pump), 659 with the RA and 502 with the RITA, respectively, in two affiliated hospitals. Data were prospectively collected, and late mortality was determined from the Social Security Death Index. Propensity matching, based on preoperative and operative variables, identified 202 matched pairs from each group. RESULTS: Long-term survival was similar for matched patients. Mortality, myocardial infarction, reoperation for bleeding, stroke, sepsis, and renal failure were not significantly different between groups. However, deep sternal wound infection (p<0.035) and respiratory failure (p<0.048) favored the RA group, in which the total major adverse events were significantly fewer (p=0.002). CONCLUSIONS: In diabetic patients undergoing multivessel revascularization with either RA or RITA grafts to the circumflex coronary, long-term survival is similar. However, RA patients experienced significantly fewer respiratory or sternal wound adverse events. The RA is the preferred conduit to extend to more diabetic patients the recognized survival benefit of a multiple arterial graft strategy.

The second best arterial graft: a propensity analysis of the radial artery versus the free right internal thoracic artery to bypass the circumflex coronary artery.

OBJECTIVE: We sought to determine if the radial artery (RA) or the free right internal thoracic artery (RITA) is the better conduit to bypass the circumflex coronary artery during coronary artery bypass grafting (CABG) using the left internal thoracic artery (LITA). METHODS: Propensity matching was performed on 2488 CABG-LITA patients from 2 affiliated centers, resulting in 528 pairs who received either a RA at one center or a free RITA at the other center to bypass the circumflex coronary artery from 1995 to 2009. RESULTS: Kaplan Meier estimated 1-, 5-, 10-, and 15-year survival rates were 99%, 95%, 85%, and 76% for RA patients, respectively, and 97%, 92%, 80%, and 71% for RITA patients, respectively (P = .060). Major adverse events (MAEs) were fewer in the RA group (7.6% vs 14.0%; P = .001) and use of the RA was a significant predictor of reduced MAEs (odds ratio [OR], 0.48; P = .002) in all patients and especially in diabetic (OR, 0.32; P = .003), older (OR, 0.40; P = .009), obese (OR, 0.15; P < .001), and chronic obstructive pulmonary disease (COPD) (OR, 0.05; P = .016) patients. However, survival was better with RA only in COPD (hazard ratio, 0.49; P = .045) and older (hazard ratio, 0.71; P = .050) patients. Overall RA patency (83.9%) was similar to RITA patency (87.4%) at a mean of 5.1 ± 3.8 years (P = .155). CONCLUSIONS: Long-term survival is similar in CABG-LITA patients using either a RA or free RITA graft to bypass the circumflex coronary artery. RA grafting has fewer MAEs, a similar patency to RITA, and improves survival in older and COPD patients. The choice of the second arterial conduit should be guided by patient profiles and surgeon preferences.

Role of mitral valve plication in the surgical management of hypertrophic cardiomyopathy.

BACKGROUND: We have previously reported our 3-step repair for obstructive hypertrophic cardiomyopathy (HCM) consisting of resection of the septum, horizontal plication of the anterior mitral leaflet (AML), and release of abnormal papillary muscle attachments. This article reviews our complete experience with surgical management of HCM to better understand the role and relevance of mitral plication. METHODS: From 1997 to 2011, 132 patients with HCM underwent surgical treatment at our institution. Eighty-two patients (62%) received AML plication based on selection criteria and were classified as group A; patients in group B did not receive plication. All patients underwent preoperative and postoperative echocardiography. Long-term clinical follow-up was obtained by review of scheduled echocardiograms and direct patient interview. RESULTS: The average age of all patients was 55.5 years. Operative mortality was 0%. The mean left ventricular outflow tract (LVOT) gradient decreased from 118±41 mm Hg to 6±13 mm Hg (p<0.0001). Mean mitral regurgitation improved from 2.4±1.0 to 0.5±0.7 (p<0.0001). Postoperatively, 96.2% of patients had no residual systolic anterior motion (SAM). Significant improvements in heart failure classification and quality of life scores were noted for all patients. Comparison of groups A and B showed no statistically significant differences in outcomes, complications, or survival. Survival at 1, 5, and 10 years was 98%, 98%, and 92%, respectively. CONCLUSIONS: The heterogeneity of the pathologic process in HCM supports detailed analysis of the septum, mitral leaflets, and subvalvular apparatus. Surgical management of HCM that includes horizontal plication of a lax and elongated AML is safe and results in durable clinical and echocardiographic improvement.

Does surgical relief of obstruction improve prognosis for hypertrophic cardiomyopathy?

Unique genetic characteristics of hypertrophic cardiomyopathy (HCM), including heterogeneity and incomplete penetrance, have made making predictions about prognosis complex. We reviewed data from septal myectomy results as published from 1980 to 2011, most of which come from specialized tertiary care centers. We also performed a retrospective review of 132 consecutive patients who underwent HCM surgery at our institution. At a mean follow-up of 4.2 ± 3.2 years (range, 3 days to 14.2 years), there were no deaths within 30 days of surgery for our cohort. Over the course of 15 years, 2 deaths occurred in older patients, both of whom had surgery for HCM along with additional cardiac procedures. Age, the presence of comorbidities, and concomitant cardiac procedures were not statistically significant risk factors for mortality. Overall survival at 1, 5, and 10 years was excellent: 99%, 99%, and 92%, respectively. Surgical myectomy has been proven to be a safe and effective procedure for symptomatic obstructive HCM, and it confers excellent survival similar to that of the healthy population.