Prognostic utility of cardiopulmonary exercise testing indices in arrhythmogenic right ventricular cardiomyopathy

Introduction

Cardiopulmonary exercise testing (CPET) has an established role in the clinical evaluation of exercise intolerance and in the risk stratification of patients with heart failure. There is limited data assessing its prognostic utility in the evaluation of patients with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC). The predisposition of patients with ARVC for ventricular arrhythmias and sudden cardiac death has led to recommendations for exercise restrictions and limits our understanding of how the impairment in oxygen extraction and cardiac output impact disease progression and outcomes in these patients.

Purpose

We examined the association between CPET indices and event free survival (time to mortality or cardiac transplantation) in patients with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC).

Methods

Patients with definite ARVC based on 2010 task force criteria and genetically positive were enrolled into our institutional ARVC registry. 43 patients underwent CPET and have been included in our analyses. Indications for testing included: Evaluation of exercise-induced palpitations/arrhythmias or syncope (37%), pharmacotherapy optimization (28%), heart failure evaluation (19%), and ARVC management decisions (16%). CPET data (peak oxygen consumption (pVO2), respiratory exchange ratio (RER), and ventilatory efficiency (VE/VCO2) were assessed in patients at time of initial evaluation. Median follow-up time was 4.9 years (IQR 9 years).

Results

126 patients were studied (age 43.7+ 15 yrs; 41% women; LVEF 57+ 11%; 15% with LVEF <50%) and 43 underwent CPET evaluation. 41 patients (95%) performed at near maximal effort (RER >1) and no fatal events were reported during testing. During the follow up period, the outcome (death or cardiac transplantation) occurred in 31 patients. On Kaplan Meier analysis, pVO2 ≤14 mL/kg/min was associated with worse outcomes (unadjusted p<0.001). Peak oxygen consumption (pVO2) ≤14 mL/kg/min and ventilatory efficiency (VE/VCO2) >34 were associated with shorter event free survival (HR 5.58, p=0.002 and HR 5.56 p=0.005, respectively). After adjusting for age, sex, and right ventricular function, the association between peak oxygen consumption (pVO2) and event free survival remained significant (p=0.02).

Conclusions

In patients with ARVC, peak oxygen consumption (pVO2) was a prognostic indicator of worse outcomes. Our findings suggest a potential role for pVO2 in disease surveillance and early assessment for advanced heart failure therapies.

Figure 1. KM plot pVO2 & event free survival

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Mayo Clinic

Left ventricular filling pressure and survival following aortic valve replacement for severe aortic stenosis

OBJECTIVE

To determine whether echocardiography-derived left ventricular filling pressure influences survival in patients with severe aortic stenosis (AS) undergoing aortic valve replacement (AVR).

METHODS

We retrospectively reviewed 1383 consecutive patients with severe AS, normal ejection fraction and interpretable filling pressure undergoing AVR. Left ventricular filling pressure was determined according to current guidelines using mitral inflow, mitral annular tissue Doppler, estimated right ventricular systolic pressure and left atrial volume index. Cox proportional hazards regression was used to assess the influence of various parameters on mortality.

RESULTS

Age was 75±10 years and 552 (40%) were female. Left ventricular filling pressure was normal in 325 (23%), indeterminate in 463 (33%) and increased in 595 (43%). Mean follow-up was 7.3±3.7 years, and mortality was 1.2%, 4.2% and 18.9% at 30 days and 1 and 5 years, respectively. Compared with patients with normal filling pressure, patients with increased filling pressure were older (78±9 vs 70±12, p<0.001), more often female (45% vs 35%, p=0.002) and were more likely to have New York Heart Association class III-IV symptoms (35% vs 24%, p=0.004), coronary artery disease (55% vs 42%, p<0.001) and concentric left ventricular hypertrophy (63% vs 37%, p<0.001). After correction for other factors, increased left ventricular filling pressure remained an independent predictor of mortality after successful AVR (adjusted HR 1.45 (95% CI 1.16 to 1.81), p=0.005).

CONCLUSIONS

Preoperative increased left ventricular filling pressure is common in patients with AS undergoing AVR and has important prognostic implications, regardless of symptom status. Future prospective studies should consider whether patients with increased filling pressure would benefit from earlier operation.

3260Prognostic value of cardiac power reserve in patients with normal left ventricular ejection fraction undergoing exercise stress echocardiography

Background

Cardiac power output-to-mass (CPOM) ratio is a measure of myocardial performance that incorporates both pressure and flow output, normalized to left ventricular (LV) mass generating that cardiac work. Prior small studies have shown that CPOM predicts outcomes in patients with ischemic cardiomyopathy and reduced LV ejection fraction (EF). We sought to evaluate the prognostic significance of peak exercise CPOM and power reserve (increase from rest to peak exercise) in patients with normal EF.

Methods and results

Retrospective study in 24,783 patients (age 59±13 years, 45% females) with EF≥50% and no significant valve disease or right ventricular (RV) dysfunction, undergoing exercise stress echocardiography between 2004–2018. CPOM was calculated as previously described (0.222 x cardiac output x mean blood pressure / LV mass) and expressed in Watts/100g myocardium. Power reserve was calculated as difference in CPOM between peak stress and rest. All-cause mortality was the primary endpoint. Patients were divided into quartiles of power reserve. Patients with higher power reserve were younger, had higher blood pressure and heart rate, lower LV mass, and lower prevalence of prior myocardial infarction. (Table). During follow-up (median (IQR) 3.9 (0.6–8.3) years), 931 (3.8%) patients died. Progressively lower power reserve was associated with increasing mortality (Figure A). Compared to patients with abnormal stress test, patients with the lowest power reserve but otherwise normal stress test had the same survival as those with infarction/cardiomyopathy or ischemia on stress test (Figure B). Resting CPOM had lower predictive value. After adjusting for age, sex, METs achieved, ischemia/infarction on stress test results, and diastolic function grade, both peak exercise CPOM and power reserve were independent predictors of mortality (p<0.0001), incremental to conventional measures.

Conclusion

Cardiac power output and reserve measured during exercise stress echo provides independent prognostic information in patients with normal resting EF and no significant valve disease or RV dysfunction. The survival of patients with low power reserve but normal stress test was similar to patients with prior infarction/ cardiomyopathy or ischemia on stress test.

Long-Term Sirolimus for Primary Immunosuppression in Heart Transplant Recipients

BACKGROUND

Small studies have reported superiority of sirolimus (SRL) over calcineurin inhibitor (CNI) in mitigating cardiac allograft vasculopathy (CAV) after heart transplantation (HT). However, data on the long-term effect on CAV progression and clinical outcomes are lacking.

OBJECTIVES

The aim of this study was to test the long-term safety and efficacy of conversion from CNI to SRL as maintenance therapy on CAV progression and outcomes after HT.

METHODS

A cohort of 402 patients who underwent HT and were either treated with CNI alone (n = 134) or converted from CNI to SRL (n = 268) as primary immunosuppression was analyzed. CAV progression was assessed using serial coronary intravascular ultrasound during treatment with CNI (n = 99) and after conversion to SRL (n = 235) in patients who underwent at least 2 intravascular ultrasound studies.

RESULTS

The progression in plaque volume (2.8 ± 2.3 mm³/mm vs. 0.46 ± 1.8 mm³/mm; p < 0.0001) and plaque index (plaque volume-to-vessel volume ratio) (12.2 ± 9.6% vs. 1.1 ± 7.9%; p < 0.0001) were significantly attenuated when treated with SRL compared with CNI. Over a mean follow-up period of 8.9 years from time of HT, all-cause mortality occurred in 25.6% of the patients and was lower during treatment with SRL compared with CNI (adjusted hazard ratio: 0.47; 95% confidence interval: 0.31 to 0.70; p = 0.0002), and CAV-related events were also less frequent during treatment with SRL (adjusted hazard ratio: 0.35; 95% confidence interval: 0.21 to 0.59; p < 0.0001). Further analyses suggested more attenuation of CAV and more favorable clinical outcomes with earlier conversion to SRL (≤2 years) compared with late conversion (>2 years) after HT.

CONCLUSIONS

Early conversion to SRL is associated with attenuated CAV progression and with lower long-term mortality and fewer CAV-related events compared with continued CNI use.

Rare recurrence of apical ballooning (takotsubo) syndrome in an elderly man

Apical ballooning syndrome (ABS) is an under recognised clinical entity characterised by acute reversible left ventricular systolic dysfunction that mimics acute myocardial infarction in the absence of obstructive coronary artery disease; typically occurring in the setting of profound stress.¹ ABS disproportionately affects older women and recurrences are infrequent. We, hereby, describe a rare phenomenon of recurrent ABS in an elderly male patient, 10 years apart, presenting with the same left ventricular morphological appearance following non-cardiac surgeries. The case illustrates the importance of considering ABS in the differential diagnosis of perioperative acute myocardial infarction in older men undergoing major surgery.

A Rare Catch in a Nonhealing Wound

INTRODUCTION

Mycobacterium smegmatis is a common microbe found in soil, dust, and water that rarely causes infections in humans.

CASE REPORT

A 45-year-old man with a past medical history of hypertension presented with a nonhealing surgical wound in his anterior chest wall, measuring 0.5 cm x 0.5 cm x 0.3 cm with minimal serosanguinous drainage, that had been present for more than 1 year. Wound swab showed M smegmatis. He required a 3-month course of antibiotic treatment and advanced wound care that included packing the sinus wounds with silver-alginate dressings for the first 2 weeks followed by iodoform packing; once the infection and drainage had improved after 2 months of treatment, packing was changed to a collagen dressing. He responded well to treatment, and the ulcers completely closed at the end of his 3-month course.

CONCLUSIONS

This case illustrates the importance of considering atypical microbial infections in the workup for chronic nonhealing wounds.

Timing of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor initiation and allograft vasculopathy progression and outcomes in heart transplant recipients

Aims

Early studies from the 1990s have shown that statins improve survival and attenuate cardiac allograft vasculopathy (CAV). However, little contemporary data are available on the incremental benefit of statins with the current use of new‐generation immunosuppressive agents and the use of coronary intravascular ultrasound for assessment of CAV. We sought to investigate the effect of early statin (ES) as compared with late statin (LS) initiation after heart transplantation (HT) on long‐term CAV progression and clinical outcomes in a large contemporary HT cohort.

Methods and results

We analysed a cohort of 409 adult HT recipients. CAV progression was assessed by serial coronary intravascular ultrasound volumetric measurements of the differences between baseline and last follow‐up plaque volume (PV) and plaque index (PV/vessel volume ratio). CAV progression and clinical outcomes were compared between the ES (<2 years after HT) and the LS (>2 years after HT) groups. During a median follow‐up of 8.2 years, ES resulted in significantly lower change (Δ) of plaque index (+3.8% ± 1.7% vs. +8.2% ± 3.6%; P = 0.0008) and PV (+0.8 ± 0.3 vs. +1.9 ± 1.2; P = 0.045) compared with LS group. In a Cox proportional hazards regression model and after adjustment for baseline characteristics, ES was associated with a 52% decreased risk of CAV‐associated events (hazard ratio 0.48, 95% confidence interval: 0.27–0.91; P = 0.025) and a 42% decreased risk of the composite endpoint of all‐cause mortality and CAV‐associated events (hazard ratio 0.58, 95% confidence interval: 0.38–0.91; P = 0.019).

Conclusions

Early initiation of statin therapy after HT results in attenuated CAV progression as well as in decreased CAV‐related events and mortality.

Uric acid is an independent predictor of cardiac allograft vasculopathy after heart transplantation

BACKGROUND

Cardiac allograft vasculopathy (CAV) is a major complication after heart transplantation (HT). Uric acid (UA) may play a role in CAV due to its role in stimulating T-cell-mediated immunity. Sirolimus is associated with CAV attenuation through a number of mechanisms, including immune-mediated effects. We aimed to determine whether UA is an independent predictor of CAV and whether conversion to sirolimus as primary immunosuppression modulates UA levels.

METHODS

We retrospectively analyzed a cohort of 224 patients who underwent HT between 2004 and 2015 and had serial coronary intravascular ultrasound (IVUS) studies. Serum UA levels were measured at baseline and last follow-up IVUS in all participants. CAV progression was assessed by measuring the change in plaque volume (ΔPV) and plaque index (ratio of plaque volume to vessel volume [ΔPI]) between last follow-up and baseline IVUS after correction for time of follow-up.

RESULTS

Patients with high (≥7 mg/dl) compared with low (<7 mg/dl) UA had increased median ΔPV (0.33 [interquartile range 0.08 to 0.93] vs 0.07 [-0.17 to 0.38] mm³/mm/year; p < 0.001) and ΔPI (2.0% [0.31% to 3.9%] vs 0.33% [-1.2% to 2.0%]; p < 0.001). Elevated UA levels were associated with a significantly increased risk of developing significant CAV progression (ΔPV >0.50 mm³/mm) (hazard ratio 2.2, 95% confidence interval 1.1 to 4.6; p = 0.037). Sirolimus resulted in decreased UA levels (5.8 ± 1.4 vs 5.2 ± 1.5; p = 0.002) and patients converted to sirolimus and had low UA levels had the least CAV progression (p < 0.001). After adjustment for potential confounders, change in UA level was also an independent predictor of CAV progression.

CONCLUSIONS

UA is an independent predictor of CAV after HT. Sirolimus is associated with decreased UA levels and may explain one of the mechanisms by which sirolimus attenuates CAV progression.

Abstract 343: Association Between Electrocardiographic Parameters and Coronary Atherosclerotic Burden in Symptomatic Patients Without History of Coronary Artery Disease

Introduction: Coronary artery calcium score (CACS) and the electrocardiogram (ECG) are tests available in the evaluation and risk stratification of coronary heart disease risk. The aim of this study is to evaluate the association between conduction abnormalities detected by ECG and coronary atherosclerotic burden determined by CACS in symptomatic patients with no history of coronary artery disease (CAD).

Methods: This is a cross-sectional study of 843 consecutive patients without history of CAD who presented with chest pain to our emergency department. All patients were evaluated with ECG and CACS by MDCT. The cohort was categorized into 4 groups: CACS 0, 1-100, 101-400, and >400. PR prolongation was defined as PR interval >200 ms. QTc prolongation was defined as normal (<420 ms), mild (420 [[Unable to Display Character: &#8211;]] 440ms) and moderate-to-severe (>440ms). Other ECG parameters evaluated include bundle branch blocks (BBB), ST segment changes, and T wave abnormalities.

Results: The cohort had a mean age of 54 ± 13 years and 44% were male. Median Framingham 10-year risk for cardiovascular disease was 5% (Interquartile range; IQR 1% - 16%). 59% of the cohort had CACS 0; 22.7% (CACS 1-100), 9.5% (CACs 101-400) and 8.8% (CACS >400). PR prolongation was present in 5% of the cohort. 66% had normal QTc and 34% had prolonged QTc - mild (180), moderate-to-severe (105). In multivariate analysis adjusted for Framingham risk, PR prolongation was independently associated with presence (OR 3.22; 95%CI 1.08, 1.12; p<0.001) and severity (CACS>400) of coronary calcification (OR 2.51; 95%CI 1.10, 5.75; p=0.03). Similarly, QTc prolongation was independently associated with presence (mild: OR 1.01; 95%CI 0.70, 1.46; p=0.96, moderate-to-severe: OR 1.64; 95%CI 1.05, 2.56; p=0.03) and severity (CACS>100) of coronary calcification (mild: OR 1.66; 95%CI 1.10, 2.53; p=0.02, moderate-to-severe: OR 2.05; 95%CI 1.26, 3.35; p=0.004). BBB (3.6%), ST segment changes (11.9%), and T wave abnormalities (22.7%) were not associated with the presence or extent of coronary calcification.

Conclusion: In patients without history of CAD, PR and QTc prolongation were independently associated with presence and severity of coronary atherosclerotic burden detected by CACS, while BBB, ST segment and T wave changes were not.

Association Between Hematological Indices and Coronary Calcification in Symptomatic Patients without History of Coronary Artery Disease

Background:

Atherosclerotic coronary artery disease (CAD) has long been shown to involve chronic low-grade subclinical inflammation. However, whether there is association between hematological indices assessed by complete blood count (CBC) and coronary atherosclerotic burden has not been well studied.

Materials and Methods:

Consecutive 868 patients without known CAD who presented with acute chest pain to emergency department and underwent coronary artery calcium (CAC) scoring evaluation by multi-detector cardiac computed tomography were included in our study. Clinical characteristics and CBC indices were compared among different CAC groups.

Results:

The cohort comprised 60% male with a mean age of 61 (SD = 14) years. Median Framingham risk of CAD was 4% (range 1-16%). Median CAC score was 0 (IQR 0-43). Higher CAC groups had significantly higher Framingham risk of CAD than lower CAC groups (P < 0.001). Among different CAC categories, there was no statistically significant difference in hemoglobin level (p 0.45), mean corpuscular volume (p 0.43), mean corpuscular hemoglobin (p 0.28), mean corpuscular hemoglobin volume (p 0.36), red cell distribution width (0.42), total white blood cell counts (p 0.291), neutrophil counts (p 0.352), lymphocyte counts (p 0.92), neutrophil to lymphocyte ratio (p 0.68), monocyte count (p 0.48), and platelet counts (p 0.25).

Conclusion:

Our study did not detect significant association between hematological indices assessed with CBC and coronary calcification in symptomatic patients without known CAD.

Abstract 158: Red Blood Cell Indices and Coronary Calcification in Patients Without a History of Coronary Artery Disease

Introduction: This study aimed to investigate associations of red cell distribution width (RDW), RBC mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) with coronary artery calcium score (CACS) in patients without history of coronary artery disease (CAD).

Methods: In this cross-sectional study, 832 consecutive patients without history of CAD who presented with acute chest pain and underwent coronary artery calcium scoring by MDCT were included. Differences in CACS among multiple RBC indices categories which were high RDW (>55 fL) VS low-to-normal RDW, low MCV (<80 fL) VS normal-to-high MCV, low MCH (<27 pg) VS normal-to-high MCH, low MCHC (<31 g/dL) VS normal-to-high MCHC were statistically calculated.

Results: The cohort comprised of 60% men (500 of 832) with mean age of 59±14 years. Median Framingham’s 10-year risk for cardiovascular disease was 4% (Interquartile range; IQR 1%-16%). Sixty percent of patients had zero CACS followed by 21.5% with CACS 1-100, 9.9% with CACS 101-400 and 8.1% with CACS>400. Mean ± SD of the RBC indices were 43±14 fL for RDW, 88±6 fL for MCV, 30±2 pg for MCH and 34±2 g/dL for MCHC. Compared to patients with normal-to-high MCV, those with low MCV (n=73) had significant lower CACS (0; IQR 0-5 VS 0; IQR 0-49; p 0.047). There was no statistically significant difference in CACS between RDW groups (p 0.45), MCH groups (p 0.19), MCHC groups (p 0.26) as shown in the figure. Multivariate analysis showed no statistically significant association of all the RBC indices with either CACS>0 (high RDW - p 0.83, low MCV - p 0.17, low MCH - p 0.26, low MCHC − p 0.06) or CACS>100 (high RDW - p 0.69, low MCV - p 0.18, low MCH - p 0.93, low MCHC − p 0.77).

Conclusion: Our study did not show significant association of RDW, MCV, MCH and MCHC with either presence or severity of coronary calcification in patients without history of CAD

Abstract 157: Association Between Monocyte Count and Coronary Calcification in Patients Without a History of Coronary Artery Disease

Introduction: This study aimed to investigate associations between monocyte count derived from complete blood count and coronary artery calcium score (CACS) in patients without history of coronary artery disease (CAD).

Methods: In this cross-sectional study, 831 consecutive patients without history of CAD who presented with chest pain and underwent coronary artery calcium scoring by MDCT were included. Patients with any clinical signs of infection were excluded. High monocyte count was defined as absolute monocyte count of > 950/uL. Presence of coronary calcification and moderate-to-severe coronary calcification were determined when CACS>0 and CACS>100 respectively.

Results: The cohort comprised of 60% men with mean age of 59±14 years. Median Framingham’s 10-year risk for cardiovascular disease was 4% (Interquartile range; IQR 1%-16%). Sixty percent of patients had zero CACS followed by 21.5% with CACS 1-100, 9.9% with CACS 101-400 and 8.1% with CACS>400. Mean ± SD absolute monocyte count was 588±379 /uL. There was no statistically significant difference in rate of CACS>0 between high monocyte count group and normal monocyte count group (p 0.83). In patients with non-zero CACS (N=328), those with absolute monocyte count > 90 percentile had higher rate of CACS>100 than those in the bottom 10 percentile (55.9% VS 30%; p 0.037) as shown in the left figure. Those with high monocyte count had higher rate of CACS>100 than those with normal monocyte count (68.4% VS 44%; p = 0.038) as shown in the right figure. In multivariate regression analysis, high monocyte count was associated with CACS>100 (HR 2.84; 95% confidence interval 1.05, 7.73; p = 0.040).

Conclusion: In patients without history of CAD, high monocyte count was not associated with presence of coronary calcification. However, high monocyte count is independently associated with more severe calcification in those with coronary calcification.