Impact of perioperative right ventricular assist device on ventricular arrhythmias in patients with continuous flow left ventricular assist device

Background

Patients with continuous flow left ventricular assist device (LVAD) may develop right ventricular failure in perioperative period of LVAD implantation. Some of these patients require temporary support with right ventricular assist device (RVAD). There is paucity of data regarding the impact of RVAD support on incidence of ventricular arrhythmias (VA) in LVAD patients.

Purpose

To assess the impact of perioperative RVAD support on the incidence of VA in the first 6 months after LVAD implant.

Methods

This is a retrospective study including 316 patients undergoing LVAD implantation at the University of Nebraska Medical Center, USA since 2012. Patients were divided into 2 groups- those who required perioperative RVAD support (BiVAD group) and those who did not require it (LVAD only group). VA was defined as any sustained ventricular tachyarrhythmia lasting more than 30 seconds or requiring therapy from implantable cardioverter-defibrillator. Incidence of VA in the first 6 months post-LVAD implantation was analyzed and compared between the groups using Cox proportional hazards regression analysis.

Results

Out of 316 total patients, 52 (16%) patients required RVAD support. The difference in age, gender, race and medications between the two groups was not statistically significant. The patients in BiVAD group had a higher incidence of post-LVAD VA (35%) as compared to LVAD only group (21%). On Cox proportional hazards regression analysis, the difference was found to be statistically significant even after adjusting for history of pre-LVAD VAs (HR: 2.27; p=0.02) (Figure 1).

Conclusion

In this large single center cohort of LVAD patients, we noticed a statistically higher incidence of VA in subgroup of patients requiring perioperative RVAD support.

Figure 1

Funding Acknowledgement

Type of funding source: None

P504VT ablation outcomes and predictors in a UK population- validating existing predictors and novel markers

Background

Radiofrequency catheter ablation (CA) can reduce ventricular tachycardia (VT) burden and registry data suggests an improvement in mortality. However, there is significant heterogeneity in patient morbidity and VT phenotype. A risk prediction model derived from observational data has suggested pre-procedural left ventricular (LV) function, age and underlying ischaemic cardiomyopathy are associated with greater post-procedural mortality. Validation of proposed factors in clinical practice is required to facilitate comprehensive pre-procedural risk stratification and inform decision making.

Purpose

To determine whether proposed pre-procedural predictors of mortality after VTCA are valid in a UK population and explore any association with other predictors.

Method

Patients undergoing VTCA at a tertiary electrophysiology centre between 06/07/16 and 31/07/19 were included. Pre-specified characteristics and mortality follow-up data were analysed from electronic health records. Cox regression analysis was undertaken to determine association with mortality.

Results

161 patients with mean age of 63 ±15.9 years underwent VTCA of whom 133 (83%) were male. During the follow-up  period (16 months, 13-24; median, 1st-3rd quartile) 16 patients died. No deaths occured in the 27 (16%) patients with structurally normal hearts. Chronic kidney disease (CKD) stage III-IV (HR 14.73 [4.9-44.4]), LV ejection fraction <35% (HR 7.13 [1.59-31.88]), underlying ischaemic cardiomyopathy (HR 6.17 [1.37-27.85]), LV internal diameter (LVID) (1.08 [1.02-1.15]) and age (HR 1.08 [1.02-1.14]) were associated with significantly greater mortality risk (Table 1) (Figure 1).

Conclusion

Proposed risk stratifying factors are validated in our UK centre’s experience. Additionally, CKD and baseline LVID appear to be associated with mortality in our population and warrant further study.

Risk factor Hazard ratio Lower confidence interval Upper confidence interval P-value Atrial fibrillation (yes/no) 0.14 0.02 1.11 0.06 Age (years) 1.08 1.02 1.14 <0.01 Diabetes (yes/no) 2.43 0.85 6.92 0.10 Chronic kidney disease (yes/no) 14.73 4.88 44.41 <0.01 Ischaemic cardiomyopathy (yes/no) 6.17 1.37 27.85 0.02 LV EF <35% (yes/no) 7.13 1.59 31.88 <0.01 LV internal diameter (mm) 1.08 1.02 1.15 <0.01 Procedural urgency (urgent/elective) 1.12 0.57 2.20 0.75 Table 1: Association between baseline risk factors and mortality risk after VT catheter ablation

Abstract Figure 1: Kaplan-Meier survival curves

Incidence of Immune Related Adverse Events in Patients Treated with Immune Checkpoint Inhibitors, Case Series from Two Tertiary Care Centeers in Dubai, UAE

Introduction:

Immune checkpoint inhibitors (ICI) represent a major component of systemic therapy in advanced malignancy. Studies have reported unique spectrum of toxicity profile of ICI as compared to systemic chemotherapy. Aim of this study is to evaluate toxicities of ICI in our population and to compare this with published data.

Material and Methods:

We retrospectively reviewed medical records of patients treated with ICI at Dubai hospital and American hospital Dubai from November 2015 to April 2019. After patient identification from hospitals cancer registry, data regarding patients’ demographics, cancer type, type of ICI, adverse events, and duration of treatment were collected.

Results:

Forty-Five patients were identified with median age of 60 (27-80) years. 27 (60%) patients were male and 18 (40%) were female. Underlying diagnosis was lung cancer (n=25), renal cell cancer (n=6), melanoma (n=5), bladder cancer (n=3), Hodgkins lymphoma (n=3) and other malignancies (n=3). Majority of patients received Nivolumab (n=20, 44%) followed by Pembrolizumab (n=19, 42%), Atezolizumab (n=4, 9%) and Durvalumab (n=2, 5%) respectively. Thyroid dysfunction was the most common side effect observed in 17 (38%) patients including hypothyroidism (n=12, 27%) and hyperthyroidism (n=5, 11%). 53 % patients treated with Nivolumab developed thyroid dysfunction as compared to Pembrolizumab (22%). 7 patients (16%) had elevated liver enzymes. Grade II and III hepatotoxicity was noted in 1 patient (2.2 %) each. One patient (2.2 %) developed grade II skin toxicity. One patient (2.2 %) developed grade III colitis. Grade II, III and IV pneumonitis was observed in 2 (4.4 %), 1 (2.2%) and 1 (2.2%) patient respectively. Immune mediated adverse events were managed according to standard guidelines and 2 patients (4.4 %) had treatment discontinuation due to grade IV Pneumonitis and grade III Colitis.

Conclusion:

Our study reports relatively higher incidence of thyroid adverse events in patients treated with ICI. The incidence of grade III-IV immune related toxicity remains low. Overall treatment with ICI was tolerated reasonably well and toxicity was manageable.

Multidimensional evaluation of changes in limb function following botulinum toxin injection in persons with stroke

BACKGROUND

There are limited evidence of instrumented measures of gait and balance to determine the functional effects of botulinum toxin injections (BoNT-A) in spasticity after stroke.

OBJECTIVE

To evaluate the functional changes in gait and balance following upper limb and lower limb BoNT-A in persons with stroke.

METHODS

A pre-post prospective study of 35 stroke patients with upper and/or lower limb spasticity after focal treatment with BoNT-A. Assessments were at baseline (T0), 6-weeks (T1) and 12-weeks (T2), using validated subjective and objective physical activity measures.

RESULTS

After BoNT-A injections, significant improvements in most measures of impairments, activity and participation domains were found at T1 (p < 0.05, effect sizes (r) = 0.5-0.9). There was a significant increase in low intensity physical activity (at T1) and sedentary time reductions at both follow-up periods. Instrumented gait/balance measures showed a significant increase in cadence and turn velocity, but no changes in sway measures were found using posturography. Improvements in most outcome measures were maintained at 12-weeks.

CONCLUSION

BONT-A improved scores in most clinical measures but only in some of the objective gait/balance and physical activity measures. Further robust studies should utilize a larger sample size to better determine the benefits of BoNT-A for stroke-related spasticity.

98Mitral annular calcification, mitral valve diseases and clinical outcomes in patients undergoing transcatheter aortic valve replacement for severe aortic stenosis

Background

Mitral annular calcification (MAC) and mitral valve diseases (MVD) have been identified as strong predictors of mortality in patients undergoing transcatheter aortic valve replacement (TAVR). However, the association between MAC and MVD, and the prognostic implications in these patients remain unclear.

Purpose

This study sought to investigate the association between severity of MAC and the prevalence of MVD as well as to assess the prognostic impact of MAC depending on the presence or absence of MVD in patients undergoing TAVR.

Methods

We identified 967 patients who have comprehensive echocardiographic and computed tomographic assessment of MVD and MAC from our institutional registry that is a part of the Swiss TAVI registry (NCT01368250) between August 2007 and June 2017.

Results

Among these patients, mild or moderate MAC was present in 45.2% and severe MAC was present in 17.8%. The prevalence of MVD was significantly higher in severe MAC patients, while the prevalence in patients with mild and moderate MAC was similar to patients without MAC. Compared to patients without severe MAC and MVD, an increased risk of all-cause death at 1 year was observed in patients with severe MAC and MVD (hazard ratio [HR]: 2.81, 95% confidence interval [CI]: 1.72–4.59, p<0.001) as well as in patients with non-severe MAC and MVD (HR: 2.80, 95% CI: 1.87–4.20, p<0.001) but not in patients with severe MAC and non-MVD (HR: 0.68, 95% CI: 0.27–1.70, p=0.409). In a multivariable analysis, severe MAC concomitant with MVD was found to be an independent predictor of new permanent pacemaker implantation after TAVR (Odds ratio: 2.08, 95% CI: 1.27–3.41, p=0.004).

Conclusions

Severe MAC was associated with higher prevalence of MVD. Severe MAC concomitant with MVD was associated with increased risks of mortality at 1 year and conduction abnormalities after TAVR, whereas severe MAC without MVD was not.

2380Mechanisms of myocardial ischemia during exercise in microvascular angina

Background

Coronary microvascular dysfunction (MVD) is defined by impaired flow augmentation in response to a vasodilator, the pathophysiological basis of which is unclear. This study sought to address two major gaps in our understanding of MVD: firstly, whether diminished flow reserve is due to structural changes within the microvasculature or potentially reversible dysfunction and secondly to unravel the mechanism of exercise-induced ischemia in the absence of obstructive disease.

Methods

Simultaneous intracoronary pressure and flow velocity recordings were made in the left anterior descending artery of patients with angina and no obstructive epicardial disease (Fractional Flow Reserve >0.80). Measurements were made at rest, during adenosine-mediated hyperaemia and supine bicycle exercise. Wave intensity analysis was used to quantify waves that accelerate and decelerate coronary blood flow, coronary perfusion efficiency being defined as the proportion of total wave energy that accelerates blood flow. Patients were prospectively classified into MVD (coronary flow reserve <2.5) and controls with researchers blinded to the classification throughout the protocol. Myocardial perfusion and vascular function were assessed by 3T cardiac MRI and venous occlusion plethysmography with forearm blood flow (FBF) assessment during serial infusions of acetylcholine, adenosine and the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (L-NMMA).

Results

78 patients were enrolled (42 patients had MVD and 36 were controls), with no differences in cardiovascular risk factors between groups. The MVD group had elevated coronary blood flow (21.3±6.4 vs. 15.1±4.5cm s–1; p<0.001) and global myocardial perfusion (1.36±0.37 vs. 1.13±0.22ml/min/g; p=0.01) at rest. Maximum coronary and myocardial blood flow during hyperaemia was similar in both groups. During exercise, MVD patients achieved similar peak flow (30.5±10.0 vs. 26.3±7.7cm s–1; p=0.07) despite a higher rate-pressure product (20777±5205 vs. 17450±4710bpm.mmHg; p=0.01). Coronary perfusion efficiency, decreased with exercise in the MVD group (61±11% vs. 44±10% p<0.001) but was unchanged in controls. On MRI, MVD had lower hyperaemic endo-epicardial perfusion ratio than controls (0.94±0.08 vs. 1.04±0.13; p=0.001). Augmentation of FBF with acetylcholine was attenuated in MVD patients compared to controls (p=0.02) but the response to adenosine was similar (p=0.13). Infusion of L-NMMA caused a significantly greater reduction in FBF in MVD patients compared to controls (p<0.001).

Exercise Physiology in MVD

Conclusion

Impaired flow reserve in MVD represents a dysfunctional state, characterised by inappropriately elevated resting flow due to increased nitric-oxide synthase mediated vasodilatation. There is abnormal flow distribution in the myocardium predisposing to subendocardial ischaemia, associated with and exacerbated by impaired cardiac-coronary coupling during exercise. These novel findings may represent distinct therapeutic targets.

Acknowledgement/Funding

British Heart Foundation

3043Endotrophin, a fragment of collagen type VI, is correlated to IMT and associated with cardiovascular events in patients with atherosclerosis and diabetes: the IMI-SUMMIT cohort

Background/Introduction

Patients with micro- and macrovascular diseases, including atherosclerosis, have increased risk of cardiovascular events and early mortality. The atherosclerotic disease is characterised by accumulation of lipids, cells and proteins in the arterial wall, which includes remodelling of the extracellular matrix (ECM). Collagen type VI (COL6) is known to be over-expressed in patients with atherosclerosis. The biomarker PRO-C6, known as endotrophin, is a COL6 fragment that reflects formation of collagen type VI, and possess pro-inflammatory and pro-fibrotic activities.

Purpose

We explored whether increased endotrophin levels, measured by PRO-C6, were associated with intima-media thickness (IMT) and mortality in the IMI-SUMMIT cohort.

Methods

Circulating protein levels of PRO-C6 were measured in EDTA plasma from 1500 patients enrolled at four European University Hospitals, using an enzyme-linked immunosorbent assay. Follow-up data were available up to three years after sample collection. Associations between PRO-C6 and incidence of cardiovascular (CV) events and all-cause mortality were assessed by Kaplan-Meier curves and Cox proportional hazard regression analyses. Pearson correlation was performed to explore the association of PRO-C6, IMT and clinical variables. Known confounders defined by the Framingham Heart study (age, gender and diabetes) were included in the Cox proportional hazard regression analysis.

Results

Plasma PRO-C6 was significantly correlated with IMT in both the common carotid artery and the carotid bulb (r=0.09, p=0.002 and r=0.11, p=0.0003, respectively), HbA1c (r=0.11, p<0.0001) and C-reactive protein (r=0.14, p<0.0001). A total of 145 patients suffered from fatal or non-fatal cardiovascular events during the three-year follow-up period. Patients in the highest PRO-C6 tertile had a two-fold increased risk of experiencing a CV event during follow-up (p=0.002), independently of age, presence of CVD at baseline, type 2 diabetes, smoking and statin treatment in a regression model.

Conclusion

The present findings demonstrate that circulating levels of PRO-C6 are associated with atherosclerosis severity and increased incidence of cardiovascular events. Since PRO-C6 detects the signaling molecule endotrophin, the results may indicate that endotrophin is not only a biomarker of atherosclerotic disease, but may have a role in promoting disease progression.

Acknowledgement/Funding

This work was supported by the Danish Research Foundation, The Danish innovation foundation and the IMI-SUMMIT participants