Schaff, Hartzell V.

Abstract Background New postoperative atrial fibrillation (POAF) occurs in about 40% after cardiac surgery. Mineralocorticoid receptor antagonists (MRA) are known to reduce chronic atrial fibrillation (AF) development and burden. We examined the impact of preoperative MRA use on POAF and also examine the atrial cell type impacted by MRA treatment during cold cardiac preservation. Methods Retrospective study of 19,042 patients who underwent cardiac surgery at Mayo Clinic in Minnesota, and performed 1:3 propensity matching to obtain 298 patients on preoperative MRA matched to 894 who were not. We also separately matched patients using preoperative diuretics. Single-nuclei RNA sequencing (snRNA-seq) examined MRA’s effects on different atrial cell types in canrenone (water soluble MRA) treated human donor hearts undergoing cold preservation followed by ex-vivo reperfusion and compared gene expression to the atria of patients with AF. Results Propensity matched preoperative MRA group had less new onset POAF (19.8% vs 31.5%, P<0.001). To account for the possibility that preoperative diuretic use and volume reduction may impact POAF, we propensity matched 298 preop diuretic users that included MRA use to another 894 patients who used a non-MRA diuretic preoperatively. Those who used preoperative MRA similarly had a lower incidence of POAF (19.8% vs 33.2%, P<0.001). No survival difference was present between the propensity matched groups that used preoperative diuretics (P=0.079). Preoperative MRA use also reduced the development of paroxysmal and chronic AF at 6 years of follow up. From our snRNA-seq data, we identified a subpopulation of atrial cardiomyocytes (CM2) that had high MR expression where canrenone suppressed the increase in MR target gene expression associated with cold preservation-reperfusion. These MR targets were conversely elevated in patients with chronic AF. Canrenone also suppressed other cardiac preservation associated genes that show elevated expression in atrial macrophages and pericytes from chronic AF atria. Conclusions Our studies show that preoperative MRA use is associated with 40% reduction in POAF as well as lowering long standing AF development by about 41%. Our cold cadiac preservation-reperfusion model showed that canrenone reduced expression of MR target genes associated with chronic AF, particular in cardiomyocytes with important roles in electrical conduction. Clinical Perspective What is New? This study shows that preoperative use of mineralocorticoid receptors antagonists (MRA) is associated with a reduced incidence of new onset perioperative atrial fibrillation after cardiac surgery utilizing cardiopulmonary bypass. We show that preoperative MRA use is associated with a lower incidence of developing more chronic paroxymal or sustained atrial fibrillation. Addition of canrenone, a clinically utilized water soluble MRA, to cardioplegia solution used during cardiac preservation can attenuate atrial inflammatory reponses and reduce signaling through molecular pathways that promote atrial fibrillation. What are the clinical implications? Perioperative use of MRAs may be considered to reduce early postoperative atrial fibrillation as well as lowering the risk of developing more chronic atrial arrhythmias. These findings support pursuing a clinical trial to determine the impact of MRA use on atrial arrhythmias following cardiac surgery in the setting of cardiopulmonary bypass with cold cardiac preservation.

BACKGROUND: Pharmacological treatments for fibrocalcific aortic valve stenosis (FCAVS) have been elusive for >50 years. Here, we tested the hypothesis that reactivation of oxidized sGC (soluble guanylate cyclase), the primary receptor for nitric oxide, with ataciguat is a safe and efficacious strategy to slow progression of FCAVS. METHODS: We used quantitative real-time reverse transcription polymerase chain reaction, Western blotting, and immunohistochemistry to characterize sGC signaling and the biological effects of ataciguat on signaling cascades related to nitric oxide, calcification, and fibrosis in excised human aortic valve tissue, aortic valve interstitial cells, and mouse aortic valves. We then conducted randomized, placebo-controlled phase I (14-day safety/tolerance) and phase II (6-month efficacy) trials in patients with moderate aortic valve stenosis. RESULTS: In excised human tissue, we found robust losses in sGC signaling despite upregulation of sGC subunits. In vitro, ataciguat increased sGC signaling and reduced BMP2 (bone morphogenetic protein 2) signaling in aortic valve interstitial cells. In mice with established FCAVS, treatment with ataciguat attenuated BMP signaling and slowed progression of valve calcification and dysfunction. In a phase I, randomized, placebo-controlled trial, treatment with ataciguat for 2 weeks was safe and well tolerated in patients with moderate FCAVS ( https://www.clinicaltrials.gov ; Unique identifier: NCT02049203). In a separate phase II, randomized, placebo-controlled trial, treatment with ataciguat for 6 months slowed the progression of aortic valve calcification and tended to slow the progression of valvular and ventricular dysfunction in patients with moderate FCAVS ( https://www.clinicaltrials.gov ; Unique identifier: NCT02481258). CONCLUSIONS: Collectively, this study highlights the therapeutic potential of the targeted restoration of the diseased/inactive form of sGC for treatment of FCAVS. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02049203. URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02481258.

BACKGROUND: In severely symptomatic patients with obstructive hypertrophic cardiomyopathy (HCM), VALOR-HCM trial (Study to Evaluate Mavacamten in Adults With Symptomatic Obstructive HCM Who Are Eligible for Septal Reduction Therapy [URL: https://clinicaltrials.gov ; Unique identifier: NCT04349072]) reported that mavacamten reduced the short-term need for septal reduction therapy (SRT). The current report examined the longer-term effect of mavacamten through end of treatment at week 128. METHODS: A double-blind randomized placebo-controlled multicenter trial at 19 sites in the United States included symptomatic obstructive HCM patients referred for SRT (enrollment July 2020 through October 2021). The group initially randomized to mavacamten continued the drug for 128 weeks and the placebo to mavacamten group from week 16 to 128 (112-week exposure). Dose titrations were performed using echocardiographic left ventricular outflow tract gradient and left ventricular ejection fraction measurements. The principal end point was proportion of patients proceeding with SRT or remaining guideline-eligible at week 128. RESULTS: At week 128, 17 of 108 (15.7%) patients in the total study sample met the composite end point (7 underwent SRT, 1 was SRT-eligible, and 9 SRT-status unevaluable). Additionally, 87 of 108 (80.5%) patients demonstrated ≥1 New York Heart Association class improvement by week 128, and 52 of 108 (48.1%) demonstrated ≥2, with a sustained reduction in resting and Valsalva left ventricular outflow tract gradients of 38.2 mm Hg and 59.4 mm Hg, respectively. Ninety-five of 108 (88%) patients transitioned to commercial mavacamten. Overall, 15 of 108 (13.8%) patients (5.41 per 100 patient-years) had an left ventricular ejection fraction <50% (2 with left ventricular ejection fraction ≤30%; 1 death). Of these, 12 of 15 (80%) continued treatment. New-onset atrial fibrillation occurred in 11 (10.2%) patients (4.55 per 100 patient-years). CONCLUSIONS: In severely symptomatic obstructive HCM patients, sustained freedom from SRT was observed at 128 weeks, with nearly 90% patients remaining on long-term mavacamten. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04349072.

Description of Case: A 40-year-old woman presented with a 3-month history of dyspnea. A murmur was found on examination. Echocardiography reported moderate mitral stenosis and regurgitation with diffuse thickening and calcification of the anterior mitral leaflet (Fig1.A), thought to be due to rheumatic disease. She had runs of supraventricular tachycardias not controlled with diltiazem. Her dyspnea progressively worsened; transesophageal echocardiography(TEE) showed severe mitral stenosis and mitral regurgitation (mean gradient 18 mmHg; Fig1.B) with a dense CW Doppler (Fig 1.C) and a mass on left atrial free wall. Cardiac MRI revealed diffuse left atrial thickening with delayed enhancement of the left atrium, left atrial appendage, and extending into the right upper and left inferior pulmonary veins. The mass was initially suspected to be a thrombus. She was placed on rivaroxaban and scheduled to undergo mitral valve replacement. When she presented to our emergency department with dizziness she was found to have paroxysmal atrial fibrillation and pulmonary embolism. On admission she had an intermittent opening snap and a 1/6 mid-diastolic rumble with a 2/6 holosystolic murmur at the apex. Work-up for infectious disease and antiphospholipid syndrome was negative. NT-proBNP was mildly elevated. At surgery the mass invaded the mitral valve and the anterior, septal, and superior part of the left atrial lateral wall and could only be partially excised (Fig1.D). Pathology showed high-grade undifferentiated pleomorphic cardiac sarcoma. Discussion: This case highlights the diagnostic challenges associated with primary cardiac tumors masquerading as valvular pathology. The presentation included dyspnea, typical auscultation of mitral stenosis and features of stenosis on echocardiography. Presumptive diagnoses included rheumatic heart disease, calcific degeneration, infective endocarditis, and autoimmune processes; the atrial mass was initially thought to be a thrombus. A thorough, multidisciplinary approach to diagnosis, utilizing multimodality imaging techniques and ultimately tissue biopsy were required to make the correct diagnosis. Maintaining a broad differential when dealing with valvular masses is key, since relying solely on imaging findings may not suffice for definitive tissue diagnosis.

Background: Optimum timing of surgery for severe primary mitral regurgitation (MR) particularly in the absence of significant symptoms or echo evidence of LV impairment remains unclear. Other modalities of assessment include cardiopulmonary exercise testing (CPET) and novel echo measurements, such as LV global longitudinal strain (LVGLS). We sought to evaluate whether pre-op CPET or LVGLS are associated with survival after surgery. Methods: We identified consecutive patients who had surgery for severe primary MR between 2007 and 2017 and had pre-op CPET. Clinical and mortality data were collected from chart review and our institutional database. LVGLS was retrospectively collected by a single person blinded to patient outcomes. Primary outcome was post surgery all cause death, and we used univariable analysis to identify variables associated with all cause death. Results: We included 176 patients with median age 63 (IQR 51, 71) years, 63 patients (35.8%) were female and 31 patients (14.8%) had a history of atrial fibrillation. 165 patients (93.8%) had mitral repair, 18 (10.2%) had concomitant CABG, 22 (12.5%) had concomitant ablation procedure and 14 (8.0%) had concomitant tricuspid procedure. 114 patients (64.8%) were in NYHA Class I and 56 (31.8%) were in NYHA Class II. There was no operative mortality. Median % predicted peak VO2 (ppVO2) was 89 (74, 101), median ventilatory equivalent of carbon dioxide (VE/VCO2) was 28.0 (25.7, 31.0) l/min/l/min and median respiratory exchange ratio was 1.2 (1.1, 1.2). 73 patients (41.5%) had abnormal CPET (defined as ppVO2<85%). Median LVEF was 65 (60, 68) %, median LVESD was 35 (32, 38) mm and median LVGLS was 18.5 (16.6, 20.3) %. 45 patients (25.9%) had abnormal LVEF (defined as ≤ 60%), 11 patients (6.7%) had abnormal LVESD (defined as ≥45mm) and 35 patients (20.8%) had abnormal LVGLS (defined as <16%). At a median follow up of 10.2 (6.8, 13.2) years, there were 19 (10.8%) deaths. In the univariate analysis, age at surgery (HR 1.12, p<0.001), LVESD (HR 1.11, p=0.009), LVGLS (HR 1.11, p=0.013) and VE/VCO2 (HR 1.08, p=0.044) were associated with all cause mortality. Conclusion: A significant proportion of patients with no or mild symptoms exhibit echocardiographic evidence of LV impairment when having surgery for severe primary MR. CPET parameters such as VE/VCO2 and novel echocardiographic measurements such as LVGLS may predict risk of long term mortality and potentially inform timing of surgery in these patients.

Abstract Mitral annular calcification with severe mitral valve (MV) stenosis can be difficult to treat with conventional MV replacement. Annular decalcification can cause atrioventricular groove disruption and bleeding. An alternative is to bypass the narrowed MV using a valved left-atrial-to-left-ventricle conduit. A 48-year-old gentleman with obstructive-hypertrophic cardiomyopathy and severe calcific MV stenosis presented with progressive dyspnea, syncope, and fatigue. Medical history included hypertension, dialysis dependent ESRD, chronic-AF, pulmonary-hypertension, and NSVT. A grade III/IV mid-systolic murmur was audible at the LSE, and a grade II/IV mid-diastolic rumble. Echocardiography showed sigmoid septum with maximum thickness of 24-mm, severe calcific MV-inflow obstruction (MVA 0.87 cm2, mean gradient 15-mmHg, heart rate 60-bpm), and midventricular LVOT obstruction (resting gradient 96-mmHg). Because of NYHA class III symptoms, surgery was performed with plans for MV-bypass using a valved-conduit and midventricular myectomy. Following institution of CPB and cardioplegic arrest, the LAA was excised and a 26-mm Hemashield graft was beveled and sewn into the atriotomy. An anterolateral ventriculotomy was made near the apex of the heart and an extensive midventricular myectomy was performed through the incision. A 25-mm Hancock-II bioprosthesis was sewn into the conduit. Distal end of the conduit was beveled and anastomosed to the ventriculotomy. Postoperatively, median native-MV gradient reduced to 7-mmHg (heart rate 86-bpm). Recovery was uneventful. He was dismissed on postoperative-day 8 and continues to do well 5-months later. MV-bypass using a valved LA-to-LV conduit is safe alternative to conventional MVR for relief of severe MS with MAC, particularly in patients with oHCM who require midventricular myectomy.

Abstract Objectives To examine the clinicopathologic features of patients with polymyalgia rheumatica (PMR) who had thoracic aorta repair surgery. Findings were compared with those of a cohort of patients with giant cell arteritis (GCA) requiring thoracic aorta repair. Methods All patients evaluated at Mayo Clinic in Rochester, MN, with Current Procedural Terminology (CPT) codes for thoracic aorta repair surgery between 2000–2021 were identified. All patients were screened for prior PMR diagnosis. Patients with PMR and no signs of GCA were categorized as clinically isolated PMR. The medical records of all patients were manually reviewed, and pathologists re-examined all the aortic tissues. Results Of the 4621 patients with at least one CPT code for thoracic aorta repair surgery, 43 patients were diagnosed with clinically isolated PMR before the surgery. Detailed histopathological examination of the aortic tissues revealed active inflammation in 30/43 (70%) patients after a median (IQR) of 10.0 (4.7–13.3) years from the PMR diagnosis. When compared with aortic tissue from patients with a prior diagnosis of GCA, the aorta of patients with PMR had more severe inflammation (Grade 3: 15/30 [50%] vs 5/34 [15%], P = 0.002). Patients with PMR and thoracic aorta repair may experience a 40% increased risk of mortality compared with the general population, but this did not reach statistical significance (standardized mortality ratio: 1.40; 95% CI: 0.91–2.07). Conclusions Some patients with PMR have subclinical aortic inflammation that is detectable many years after initial diagnosis and may contribute to the development of aortic aneurysm.

Abstract Aim Describe the mechanism(s) of residual or recurrent obstruction in patients who have previously undergone septal myectomy for hypertrophic cardiomyopathy and assess early outcomes of reoperation. Method From January 1989 to March 2022, we performed 73 repeat myectomies at our institution. Patients’ demographics, operative details, echocardiographic parameters, and postoperative complications were retrieved from a prospectively maintained surgical database and electronic healthrecords. Results Median age at reoperation was 48.3 years (IQR 38.6-58.6); 51 patients were women (69.9%). 90.4% presented with NYHA class III/IV symptoms. Median interval between previous myectomy and reoperation was 2.7 years (IQR 1.2-4.5). Mechanism of obstruction was an inadequate length of previous septectomy in 41 patients (56.2%), a combination of inadequate length and midventricular obstruction in 30 (41.1%), and isolated midventricular obstruction in 2 patients (2.7%). There were no instances of recurrent LVOT obstruction due to muscle regrowth at the site of previous resection. All patients had an extended transaortic septal myectomy; 14 patients (19.2%) had concomitant transapical myectomy. Preoperatively, the median LVOT gradient was 83 mmHg (IQR 60-122), which reduced to 2 mmHg (IQR 0-7) following repeat myectomy. There were no perioperative deaths. Postoperatively, 4 patients (5.5%) developed a new CHB, necessitating PPM implantation. The 5-,10-, and 20-year survival after reoperation were 100%, 91%, and 76%, respectively. Conclusions Inadequate resection at the time of primary septal myectomy is the commonest cause of residual or recurrent obstruction in oHCM patients. However, repeat myectomy, including a combined transaortic and transapical approach has minimal risk with excellent hemodynamic and long-term survival outcomes.

Introduction: Obesity is an independent risk factor for heart failure in patients with hypertrophic cardiomyopathy (HCM). Bariatric surgery is associated with improved cardiac function in obese patients with heart failure, but the safety of this procedure has not been evaluated in HCM patients. In this study, we examined national trends and early outcomes in bariatric surgery for patients with HCM. Methods: Using the weighted discharge data from the National Inpatient Sample, we identified adult patients with HCM who underwent elective bariatric surgery for obesity between 2011 and 2017. Patients with a history of bariatric surgery or having malignant neoplasms in the esophagus, stomach, small intestine, or pancreas were excluded. Results: A total of 443 obese patients with HCM were identified, and 41.8% (n=185) had obstructive HCM. The annual number of patients increased from 18 in 2011 to 130 in 2017, and nearly half of the patients (48%) had bariatric surgery in 2016 and 2017. Overall, the median (IQR) age was 50 (43-57) years, and 85 (19%) patients were 60 years or older. Approximately 20% (n=90) of the patients had heart failure at the time of operation. Atrial fibrillation was present in 83 (19%) patients, and 22% (n=95) of the cohort had a pacemaker or automatic cardiac defibrillator implanted prior to the operation. Laparoscopic sleeve gastrectomy (72%, n=318) and laparoscopic Roux-en-Y gastric bypass (25%, n=110) were the most commonly performed bariatric procedures. Overall, patients stayed in hospital for a median (IQR) of 2 (1-2) days. During the hospital stay, 1% (n=5) of the patients had acute worsening of chronic heart failure, but there were no deaths, cardiac arrests, or cerebrovascular accidents post procedure. Conclusions: Bariatric surgery in patients with HCM is performed more frequently in recent years and is safe and associated with few perioperative complications. Given the impact of obesity on long-term survival, clinicians should strongly consider bariatric surgery for HCM patients who do not respond to conservative weight loss measures.

Introduction: Carcinoid heart disease (CHD) is a rare sequelae of hormonally active neuroendocrine tumors that often requires cardiac surgical intervention. Little is reported on cardiac implantable electronic device (CIED) implantation in the CHD patient population. Hypothesis: We sought to establish the safety and efficacy of CIED implantation in patients with CHD. Methods: We retrospectively reviewed patients with a diagnosis of CHD who underwent CIED implantation at our institution (Mayo Clinic) and evaluated indications for implant, perioperative complications, and mortality. Results: A total of 27 patients with a cumulative follow up of 75 patient-years were identified during the study period. The most common indication for device implant was high grade atrioventricular block (n=18, 66.7%). 14 (51.8%) had baseline conduction disease and 26 (96.2%) underwent cardiac surgery prior to CIED implant. The majority of devices implanted were dual chamber permanent pacemakers (PPM) (n=17, 63.0%), while other devices included single chamber PPM, epicardial PPM, chronic resynchronization devices, and intracardiac defibrillators. Peri-operative complication occurred in 6 patients (22.2%), with 2 patients requiring ICU level care. No patient suffered carcinoid crisis during implantation and there was no peri-implant mortality. Long term, 3 patients required device extraction: 1 for infection, 1 for lead related pain, and 1 for generator migration. The median time to death from implant was 2.5 years, with one-year mortality at 15%. Conclusions: In this unique cohort of patients with CHD, CIED can be performed safely. CIED most often occurred in the post cardiac surgical period and carcinoid crisis was uncommon.