Time Of Myectomy Research Articles

Surgical Outcomes of Septal Myectomy With and Without Mitral Valve Surgeries in Hypertrophic Cardiomyopathy: a National Propensity-Matched Analysis (2005 to 2020)

The management of concomitant mitral valve (MV) disease in patients with hypertrophic cardiomyopathy (HCM) remains controversial. The 2020 American Heart Association/American College of Cardiology HCM guidelines recommend that MV replacement (MVR) at the time of myectomy should not be performed for the sole purpose of relieving outflow obstruction. At the national level, limited data exist on the surgical outcomes of MV repair/replacement in patients with HCM who underwent septal myectomy (SM). Hospitalizations of patients with HCM who underwent SM between 2005 and 2020 were identified using International Classification of Diseases, Ninth and Tenth Revision codes (International Classification of Diseases, Ninth and Tenth Revision Clinical Modification/ProcedureCoding System). The 3 comparison cohorts were SM alone, MV repair, and MVR with concomitant SM. After propensity matching, 2 cohorts, SM+MVR versus SM+MV repair, were studied for surgical outcomes. Demographic characteristics, baseline co-morbidities, procedural complications, inpatient mortality, length of stay, and cost of hospitalization were compared between the propensity-matched cohorts. A total of 16,797 SM procedures were identified from 2005 to 2020. Among them, 11,470 hospitalizations had SM alone (68.2%), SM+MVR was seen in 3,101 (18.4%), and SM+MV repair comprised 2,226 (13.2%). After propensity matching, the MVR and MV repair formed the matched cohorts of 1,857. There were no significant differences in the odds of cardiogenic shock (adjusted odds ratio [aOR] 0.88, 95% confidence interval [CI] 0.63 to 1.24, p=0.49), mechanical circulatory support requirement (aOR 0.58, 95% CI 0.37 to 0.90, p=0.015), stroke (aOR 1.27, 95% CI 0.81 to 1.99, p=0.29), and major bleeding (aOR 0.52, 95% CI 0.34 to 0.79, p=0.0026) between the comparison groups. MVR, compared with MV repair, was associated with a higher risk of procedural mortality (8.02% vs 3.18%, aOR 2.98, 95% CI 2.05 to 4.33, p <0.0001), complete heart block (16.36% vs 12.15%, aOR 1.76, 95% CI 1.44 to 2.12, p <0.0001), and the need for permanent pacemaker (16.39% vs 10.62%, aOR 1.83, 95% CI 1.41 to 2.38, p <0.0001). The total length of hospital stay and median hospitalization cost was higher in the MVR group. SM in HCM concomitant with MVR is associated with higher procedural mortality and in-hospital complication risk. These real-world data support the 2020 American Heart Association/American College of Cardiology guidelines that in patients who are candidates for surgical myectomy, MVR should not be performed as part of the operative strategy for relieving outflow obstruction in HCM.

Aortic valve regurgitation following transaortic septal myectomy for obstructive hypertrophic cardiomyopathy: Incidence and influence on late outcomes

ObjectiveIn this study, we describe the incidence, sites of valve injury, and the influence of aortic valve regurgitation (AR) on outcomes of septal myectomy for obstructive hypertrophic cardiomyopathy. MethodsWe analyzed patients who underwent transaortic septal myectomy for obstructive hypertrophic cardiomyopathy from 2001 to 2022. The primary study end point was incidence of procedure-related AR, defined as the need for an unplanned aortic valve (AV) procedure or new-onset moderate AR on early postoperative echocardiography. ResultsThere were 2807 patients who underwent transaortic septal myectomy for hypertrophic cardiomyopathy and had pre- and postoperative transthoracic echocardiograms. Procedure-related AR was observed in 55 (2%) patients; 27 (1%) required unplanned AV procedures at the time of myectomy, and 29 (1%) additional patients developed moderate AR postoperatively. During follow-up, 9 total patients underwent late AV reoperation, 1 patient who developed new moderate AR postoperatively required late AVR due to severe calcific AS, and none of the patients who had unplanned AV procedures required late reoperation. The overall cumulative incidence of AV reoperation at 10 and 15 years was 1% and 5%. The predicted probability of moderate or severe AR at 5 and 10 years was 1.4% and 1.8%, respectively. There was no difference in survival comparing patients with or without early postoperative mild or worse AR (P = .69). ConclusionsProcedure-related AR was observed in 2% of patients undergoing transaortic septal myectomy, and unplanned AV procedures were necessary for half of these patients. Intraoperative identification and valve repair mitigate the impact of cusp injury on late reintervention and survival.

PO-02-157 IMPACT OF ATRIAL FIBRILLATION ON QUALITY OF LIFE IN HYPERTROPHIC CARDIOMYOPATHY

In hypertrophic cardiomyopathy (HCM) atrial fibrillation (AF) has been historically described as unrelenting, a driver for heart failure, with a decisive impact on quality of life. AF treatment has been deemed less effective in HCM due to high rates of AF recurrence. However, AF has predominantly been characterized from physicians perspective and there is no data on impact on patient reported outcome measures (PROMs). To evaluate the impact of AF on PROMs in HCM. PROMs were collected using the Atrial Fibrillation Severity Scale (AFSS) and Kansas City Cardiomyopathy Questionnaire overall summary (KCCQ-OS) reflecting symptom burden and quality of life in 250 consecutive HCM patients. Among the 250 patients, 51 (20%) were diagnosed with AF at 56±10 years of age, 6.5±5.5 years prior to evaluation and reported health status. At evaluation, 45 of the 51 AF patients (88%) were in sinus rhythm, and 6 in AF (12%) including 5 in permanent AF. Each of the 51 patients required AF treatment for symptoms: 27 (53%) solely with medications (17 with AV nodal medications and 10 on antiarrhythmic drugs); and 24 (47%) with AF ablation (16 with catheter ablation and 8 surgical Cox-Maze IV at time of myectomy). Of the 24 AF ablation patients, 15 (63%) had recurrent AF including 6 (25%) requiring multiple ablation procedures. After most recent ablation, AF burden was reported as infrequent ≤1 episode per month in 17 (71%), including 10 with ≤1 episode/year. 75% had AFSS symptom score consistent with mild symptoms, and 91% had KCCQ-OS with mild or no disability. There was no difference in either KCCQ-OS or AFSS in patients with and without AF recurrence after ablation (p=0.68). The 27 patients treated solely with medications each had recurrent AF episodes on current therapy, but 15 (56%) reported infrequent AF burden ≤1 per month including 11 with ≤1 episode/year. With treatment, 67% had AFSS symptom score consistent with mild symptoms and 82% had KCCQ-OS with mild or no disability. There was no difference in KCCQ-OS in the 51 HCM patients with AF compared to 199 patients without AF (p=0.2). Recurrent AF in HCM is common despite treatment, however episodes tend to be infrequent. With treatment, the majority of patients with AF have no or mild symptom burden. These data support that despite recurrent AF episodes after treatment, quality of life metrics are not significantly impaired for most HCM patients.

Abstract 9755: Impact of Outflow Obstruction and Septal Myectomy on Long Term Risk of New Onset Atrial Fibrillation in Hypertrophic Cardiomyopathy

Background: Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM), with patients having a 4 to 6 fold greater likelihood of developing AF as compared to the general population, and is an important cause of morbidity, impaired quality of life and embolic stroke in HCM. The impact of outflow obstruction and the influence of surgical septal myectomy on the development of new-onset AF has not been well described. Aim: To characterize the risk of new-onset AF in nonobstructive and obstructive HCM and compare to AF risk in patients after myectomy. Methods: 1767 consecutive HCM patients without prior AF history, seen at the Tufts HCM Institute between 2004 and 2019, including 712 with obstruction (outflow gradients ≥ 30mmHg at rest or following provocation) who did not undergo invasive septal reduction therapy (SRT), 552 with nonobstructive HCM (outflow gradients &lt; 30mmHg), and 503 who underwent surgical myectomy were followed for an average of 4.3 ±4.2 years for new-onset symptomatic AF. Isolated post-operative episodes of AF, i.e., occurring within the first 3 months after myectomy, were excluded from analysis. Results: Patients with obstructive HCM who did not undergo SRT had a 1.5-fold increased risk for new-onset AF as compared to nonobstructive HCM (rate onset of 2.8%/year vs.1.7%/year, p=0.04), with freedom from AF at 10-years of 72% in obstructive patients. Patients undergoing myectomy were older (52 ± 15 vs. 50 ± 15 years; p&lt;0.01), had larger LA dimension (42 ± 7 vs 40 ± 6mm; p&lt;0.01), and higher HCM-AF risk scores (22 ± 3.5 vs. 19 ± 3.8; p&lt;0.01) as compared to nonobstructive HCM. However, despite a higher predicted risk for new-onset AF at time of myectomy (2.7%/year vs. 1.5%/year), after myectomy the risk of new onset AF was no different from patients with nonobstructive HCM (hazard ratio 0.9; rate of onset of 1.8%/year vs. 1.7%/year; p=.73), with freedom from AF at 10-years of 83% post-myectomy. Conclusions: Patients with obstructive HCM have a higher risk of AF as compared to nonobstructive HCM. After myectomy risk of new-onset AF is substantially reduced, such that risk is no different from patients with nonobstructive HCM. These data demonstrate efficacy of myectomy in decreasing long term risk of AF in obstructive HCM.

Regional myocardial function at preclinical disease stage of hypertrophic cardiomyopathy in female gene variant carriers

We recently showed more severe diastolic dysfunction at the time of myectomy in female compared to male patients with obstructive hypertrophic cardiomyopathy. Early recognition of aberrant cardiac contracility using cardiovascular magnetic resonance (CMR) imaging may identify women at risk of cardiac dysfunction. To define myocardial function at an early disease stage, we studied regional cardiac function using CMR imaging with tissue tagging in asymptomatic female gene variant carriers. CMR imaging with tissue tagging was done in 13 MYBPC3, 11 MYH7 and 6 TNNT2 gene carriers and 16 age-matched controls. Regional peak circumferential strain was derived from tissue tagging images of the basal and midventricular segments of the septum and lateral wall. Left ventricular wall thickness and global function were comparable between MYBPC3, MYH7, TNNT2 carriers and controls. MYH7 gene variant carriers showed a different strain pattern as compared to the other groups, with higher septal peak circumferential strain at the basal segments compared to the lateral wall, whereas MYBPC3, TNNT2 carriers and controls showed higher strain at the lateral wall compared to the septum. Only subtle gene-specific changes in strain pattern occur in the myocardium preceding development of cardiac hypertrophy. Overall, our study shows that there are no major contractile deficits in asymptomatic females carrying a pathogenic gene variant, which would justify the use of CMR imaging for earlier diagnosis.

Management of Subaortic Left Ventricular Outflow Tract Obstruction After Aortic Valve Replacement

Residual or new left ventricular outflow tract (LVOT) obstruction after an aortic valve replacement poses special challenges with respect to operative techniques. Our study assesses this gap. From January 1993 to May 2019, 18 patients underwent a septal myectomy at Mayo Clinic for subaortic obstruction after aortic valve replacement. We evaluated their demographics, clinical presentation, and echocardiograms, and the type of prior valve replacement, need for repeat replacement, and their short- and long-term outcomes. The data were analyzed using descriptive statistics. All patients underwent septal myectomy for LVOT obstruction at a median interval of 7 years (interquartile range, 3-15 years) from their prior aortic valve procedure. Preoperatively, the median left ventricular outflow tract gradient was 57 mm Hg (interquartile range, 44-77 mm Hg); 10 patients (55.5%) had systolic anterior motion (SAM) of the mitral leaflets. Repeat replacement of the aortic valve at the time of myectomy was needed in 14 patients, and septal myectomy alone was performed in 4 patients. One hospital death occurred 34 days after myectomy and aortic valve replacement, and 2 patients needed permanent pacemaker placement for complete heart block. Septal myectomy after aortic valve replacement may be performed with repeat replacement of the valve, if there is coexisting prosthetic dysfunction, through a normally functioning bioprosthesis or through an apical approach when visualization through the aortic prosthesis is poor. The complexity of reoperation supports a liberal approach to myectomy at the time of aortic valve replacement when there is significant subaortic septal hypertrophy.

Impact of sex on timing and clinical outcome of septal myectomy for obstructive hypertrophic cardiomyopathy

BackgroundSex disparities are common in hypertrophic cardiomyopathy (HCM). Previous research has shown that at time of myectomy, women are older, have greater impairment of diastolic function and more advanced cardiac remodeling. The clinical impact of these differences is unknown. MethodThis study included 162 HCM patients (61% men) who underwent septal myectomy. Time to treatment was calculated in relation to symptom onset and diagnosis. Pre- and post-operative echocardiographic data were collected. Sex differences were assessed at baseline and in time-to-event survival analyses for the composite endpoint of all-cause mortality, cardiac transplantation, re-intervention and aborted sudden cardiac death. ResultsWomen were generally older at time of myectomy (57 vs. 49 years, p < 0.01), with similar time to treatment as measured from symptom onset (2.3 [1.3–6.0] vs. 2.8 [1.1–5.3] years, p > 0.05), but a shorter time since diagnosis compared to men (2.6 [1.2–7.0] vs. 4.3 [2.4–8.3] years, p = 0.02). Mean wall thickness and left atrial diameter were the same for men and women, but were higher in women when correcting for body surface area (absolute: 20 vs. 19 mm, 48 vs 46 mm, p ≥ 0.05; corrected: 9.7 vs. 11.2 mm/m2, 23.4 vs. 26.3 mm/m2, p < 0.01). After 5.9 [3.0–9.1] years, 15% of men and 8% of women had reached the composite endpoint (p > 0.05). ConclusionIn conclusion, although women present later in life and seem to have more advanced disease on echocardiography, time until myectomy was similar and clinical outcomes after myectomy are favourable for both men and women.

Sex-specific cardiac remodeling in early and advanced stages of hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is the most frequent genetic cardiac disease with a prevalence of 1:500 to 1:200. While most patients show obstructive HCM and a relatively stable clinical phenotype (stage II), a small group of patients progresses to end-stage HCM (stage IV) within a relatively brief period. Previous research has shown sex-differences in stage II HCM with more diastolic dysfunction in female than in male patients. Moreover, female patients more often show progression to heart failure. Here we investigated if differences in functional and structural properties of the heart may underlie sex-differences in disease progression from stage II to stage IV HCM. Cardiac tissue from stage II and IV patients was obtained during myectomy (n = 54) and heart transplantation (n = 10), respectively. Isometric force was measured in membrane-permeabilized cardiomyocytes to define active and passive myofilament force development. Titin isoform composition was assessed using gel electrophoresis, and the amount of fibrosis and capillary density were determined with histology. In accordance with disease stage-dependent adverse cardiac remodeling end-stage patients showed a thinner interventricular septal wall and larger left ventricular and atrial diameters compared to stage II patients. Cardiomyocyte contractile properties and fibrosis were comparable between stage II and IV, while capillary density was significantly lower in stage IV compared to stage II. Women showed more adverse cellular remodeling compared to men at stage II, evident from more compliant titin, more fibrosis and lower capillary density. However, the disease stage-dependent reduction in capillary density was largest in men. In conclusion, the more severe cellular remodeling in female compared to male stage II patients suggests a more advanced disease stage at the time of myectomy in women. Changes in cardiomyocyte contractile properties do not explain the progression of stage II to stage IV, while reduced capillary density may underlie disease progression to end-stage heart failure.

Septal Myectomy and Concomitant Coronary Artery Bypass Grafting for Patients With Hypertrophic Cardiomyopathy and Coronary Artery Disease

Severe coronary artery disease is associated with disproportionately increased risks of death in patients with hypertrophic cardiomyopathy. There is a paucity of data on the long-term effect of coronary revascularization at the time of myectomy. Between January 1, 1961, and October 31, 2017, 2913 adult patients underwent transaortic septal myectomy at Mayo Clinic. Concomitant coronary artery bypass grafting (CABG) was performed in 246 (8.4%). We compared baseline characteristics of patients who underwent septal myectomy with and without CABG and assessed the effect of surgical revascularization on the risk of all-cause mortality. Patients who underwent concomitant CABG were older (median [interquartile range], 66.3 [59.8-72.1] years vs 54.4 [43.5-64.8] years; P<.0001) and more likely to be male (63.0% vs 54.2%; P=.008) than those who did not undergo coronary revascularization at operation. There was no significant difference in preoperative left ventricular outflow tract gradients (55 [25-81] mm Hg vs 58 [25-88] mm Hg; P=.116). Overall operative mortality (≤30 days after surgery) was 1.0% and higher in patients who underwent concomitant CABG (2.2% vs 0.8%; P=.048). In multivariable analysis (n=2641), factors independently associated with mortality included concomitant CABG (hazard ratio [95% CI], 1.89 [1.39-2.58]; P<.0001), older age at operation (per interquartile range increase, 2.79 [1.95-3.98]; P<.0001), atrial fibrillation (1.46 [1.11-1.92]; P=.006), diabetes (1.45 [1.04-2.04]; P=.031), higher body mass index (change from 0.95 to 0.5 quantile, 1.95 [1.46-2.59]; P<.0001), and surgery performed earlier in the study period (2.02 [1.31-3.11]; P=.001). In conclusion, obstructive coronary artery disease severe enough to prompt concomitant CABG at the time of septal myectomy is an important risk factor for late mortality.

P1244Survival after septal myectomy in male and female patients with hypertrophic obstructive cardiomyopathy

Abstract In recent years, studies have debated the impact of gender on the presentation and clinical course of HCM, with research showing that at time of myectomy, women are older, have worse diastolic function and more advanced cardiac remodeling. The clinical impact of these differences is unknown. We included 221 HCM patients (57% men) who underwent septal myectomy and are followed in our center. Time to treatment was calculated in relation to symptom onset. Pre- and post-operative clinical and echocardiographic data were collected. Gender differences were assessed at baseline and in survival analyses for the composite endpoint of all-cause mortality, cardiac transplantation, re-intervention and aborted sudden cardiac death. Women were older at time of myectomy, but time until treatment was similar (table). Pre-operative echocardiographic indices were comparable among groups, but were significantly higher in women when correcting for body surface area. At three months, no differences were found in clinical and echocardiographic results. After 6.1 [2.9–10.1] years, 24% of women and 23% of men had reached the composite endpoint (p=0.30, figure). Gender comparison pre- and post-myectomy Men (n=125) Women (n=96) p value Age 49±14 54±17 0.02 Maximal wall thickness, mm 19.9±4.7 19.8±5.8 0.97 Indexed maximal wall thickness, mm/m2 9.8±2.5 11.5±4.5 0.001 Left atrial diameter, mm 48.1±7.3 45.9±7.3 0.06 Indexed left atrial diameter, mm/m2 23.5±3.5 26.5±7.5 0.002 LV end-diastolic diameter, mm 45.4±7.6 42.8±5.6 0.04 Indexed LV end-diastolic diameter, mm/m2 22.1±3.7 23.6±3.0 0.02 Gradient reduction, %* 75.1±25.0 72.9±28.6 0.63 Improvement in symptoms*† 97 (95%) 64 (89%) 0.34 MWT = maximal wall thickness; LV = left ventricle. *At three months follow-up; †Defined as a reduction of ≥1 NYHA class, measured in 102 men and 72 women. Survival after myectomy Although women present later in life and seem to have more advanced disease at time of myectomy, time to treatment is similar and survival after myectomy is excellent for both men and women.

Sex Differences at the Time of Myectomy in Hypertrophic Cardiomyopathy.

One of the first clinically detectable alterations in heart function in hypertrophic cardiomyopathy (HCM) is a decline in diastolic function. Diastolic dysfunction is caused by changes in intrinsic properties of cardiomyocytes or an increase in fibrosis. We investigated whether clinical and cellular parameters of diastolic function are different between male and female patients with HCM at the time of myectomy. Cardiac tissue from the interventricular septum of patients with HCM (27 women and 44 men) was obtained during myectomy preceded by echocardiography. At myectomy, female patients were 7 years older than male patients and showed more advanced diastolic dysfunction than men evident from significantly higher values for E/e' ratio, left ventricular filling pattern, tricuspid regurgitation velocity, and left atrial diameter indexed for body surface. Whereas most male patients (56%) showed mild (grade I) diastolic dysfunction, 50% of female patients showed grade III diastolic dysfunction. Passive tension in HCM cardiomyocytes was comparable with controls, and myofilament calcium sensitivity was higher in HCM compared with controls, but no sex differences were observed in myofilament function. In female patients with HCM, titin was more compliant, and more fibrosis was present compared with men. Differences between female and male patients with HCM remained significant after correction for age. Female patients with HCM are older at the time of myectomy and show greater impairment of diastolic function. Furthermore, left ventricular and left atrial remodeling is increased in women when corrected for body surface area. At a cellular level, HCM women showed increased compliant titin and a larger degree of interstitial fibrosis.

P2314Mitral valve replacement at time of myectomy for hypertrophic obstructive cardiomyopathy

P2314Mitral valve replacement at time of myectomy for hypertrophic obstructive cardiomyopathy

Trans-aortic Alfieri stitch at the time of septal myectomy for hypertrophic obstructive cardiomyopathy.

Systolic anterior motion (SAM) of the mitral valve, left ventricular outflow tract (LVOT) obstruction, and mitral regurgitation (MR) are known adverse outcomes that can occur after septal myectomy for hypertrophic obstructive cardiomyopathy. The objective of this study was to describe outcomes of a surgical technique to prevent these complications. We have adopted a technique where we place an Alfieri stitch in the mitral valve through the aortotomy while performing septal myectomy. A retrospective review was performed and outcomes associated with this technique were noted. Twenty-four patients underwent septal myectomy and mitral valve repair using this technique. Mean age was 57 ± 10 years. Twenty patients were in class III/IV heart failure, and all had documented SAM. Mean LVOT gradient improved from 78 ± 48 mmHg preoperatively to 19 ± 20 mmHg after myectomy (p < 0.001). No patients had postoperative SAM, and no patients required a second aortic crossclamping for mitral repair. Seventeen of 19 patients with ≥mild MR had improvement in MR. During follow-up, 16 patients had no/trivial MR, seven had mild MR, and one had moderate MR. The mean postoperative mitral gradient was 4.5 ± 3.0 mmHg. Thirteen patients had postoperative complications including one death in a patient who developed a ventricular septal defect. Trans-aortic Alfieri stitch placement during septal myectomy is feasible in most cases as an additional tool to improve MR and minimize SAM. This technique may have a role in addressing mitral disease, such as a long anterior leaflet or fibrotic mitral valve, at the time of myectomy without the need for left atriotomy for mitral exposure.