Training Pathways in Critical Care Cardiology: Competencies and Considerations for Cardiologists.

PURPOSE OF REVIEW: Critical care cardiology (CCC) is a rapidly developing field undergoing a renaissance of interest and growth to meet the well-documented population shift in the cardiac intensive care unit (CICU). With this has come the emergence of novel training paradigms that seek to combine specialties with meaningful overlap. RECENT FINDINGS: The benefit of having critical care expertise in the CICU has been clearly established; however, there is no formal or uniform CCC training pathway. Contemporary approaches seek to provide appropriate clinical and procedural experience while minimizing opportunity cost. The combination of additional cardiology subspecialties, specifically advanced heart failure or interventional cardiology, has been demonstrated. Educational tracks that integrate critical care training have generated interest but have not yet manifested. CCC training strives to meet the needs of an increasingly sick and diverse patient population while preparing trainees for fulfilling and meaningful careers. The hope is for ongoing development of novel training pathways to satisfy evolving needs.

Contemporary Trends of Clinical Outcomes in Primary Left Ventricular Assist Device Implantation and Postprocedure High-Risk Categories.

OBJECTIVE: We aimed to analyze trends of 30-day readmission and find high-risk patients associated with increased risk of mortality, resource use, and readmission after primary left ventricular assist device (LVAD) implantation. Limited data exist on the contemporary trends of readmission rates and patients at a higher risk of worse outcomes after LVAD implantation. METHODS AND RESULTS: This is a retrospective study of adults from the Nationwide Readmission Database who underwent primary durable LVAD implantation from 2010 to 2018. The main outcomes were 30-day readmission rates and their trends in patients with primary durable LVAD implantation from 2010 to 2018. This study also sought to identify patients at the highest risk for readmission, in-hospital mortality, and resource use. A total of 31,002 adults with primary durable LVAD implantation were included in the present analysis. Overall, 3808 patients (12.3%) died and 27,168 (87.6%) were discharged alive. Of those discharged alive, 8303 patients (30.6%) were readmitted within 30 days. The trend of 30-day all-cause readmission among LVAD implantation patients remained similar from 2010 to 2018 (P = .809). The in-hospital mortality rate during the index hospitalization decreased significantly (P = .014), and the mean cost of an index hospitalization increased (P = .031) during the study period. The patients with post-LVAD in-hospital cardiac, vascular, and thromboembolic complications (ie, high-risk patients) had the highest mortality, resource use, and readmission rates compared with patients without major complications. CONCLUSIONS: This study found that the readmission rates associated with LVAD implantation did not change from 2010 to 2018 and identified high-risk patients who may benefit from closer monitoring after primary LVAD implantation.

Acute Hemodynamic Effects of Sacubitril-Valsartan In Heart Failure Patients Receiving Intravenous Vasodilator and Inotropic Therapy.

BACKGROUND: Prior study has demonstrated that transitioning patients in acutely decompensated heart failure with a low cardiac output directly from intravenous (i.v.) vasoactive (ie, vasodilators or inotropes) drugs to sacubitril-valsartan (S/V) can be done safely with tolerance to the 1-month follow-up. Here, we further characterize the hemodynamic impact of S/V after patients have been optimized on vasoactive therapy. METHODS AND RESULTS: In a single-center, retrospective analysis, 25 patients with cardiac index of less than 2.2 L/min/m2 were admitted to the cardiac intensive care unit and newly initiated on angiotensin receptor-neprilysin inhibitor therapy with the guidance of invasive hemodynamic monitoring. Hemodynamic data were gathered and compared upon cardiac intensive care unit admission, after optimization with i.v. vasoactive therapy, and after S/V initiation and weaning off i.v. THERAPY: All patients who tolerated S/V (n = 20) were weaned off vasoactive medications before transfer out of cardiac intensive care unit. Patients maintained their significant improvement in cardiac index and reduction in SVR/PVR on transition from i.v. inotropic and vasodilator therapy to oral S/V. There was an increase in pulmonary artery pulsatility index with S/V therapy compared with the i.v. vasoactive phase of care. CONCLUSIONS: Patients in the cardiac intensive care unit can be successfully bridged from vasoactive i.v. therapy to oral S/V with sustained improvement in cardiac index garnered from vasoactive agents. We also observed improvement in the pulmonary artery pulsatility index and maintenance of left and right ventricular unloading with S/V. These encouraging findings merit further prospective study.

Screening for subclinical subclavian artery stenosis before coronary artery bypass grafting: Should we do it?

Atherosclerotic subclavian artery disease is detected in about 5% of patients referred for coronary artery bypass (CABG) surgery. The internal mammary artery, a branch of the subclavian artery, is the most frequently utilized graft to restore coronary circulation because of its longevity. Stenosis or occlusion of the subclavian artery can cause retrograde blood flow in the ipsilateral internal mammary artery, known as "steal," compromising coronary circulation supplied by the graft. Steal may be asymptomatic or may result in symptoms of myocardial ischemia. Symptomatic subclavian artery stenosis post bypass is referred to as coronary subclavian steal syndrome post-CABG. The incidence is not well defined, and the benefits of screening patients referred for CABG are not known. Despite the various modalities available to detect subclavian artery stenosis, current guidelines fail to provide guidance about screening high-risk patients for this entity. Detection of subclavian artery disease prior to CABG can reduce complications posed by post-mammary artery graft cardiac ischemia. This review discusses the utility of preoperative subclavian artery screening prior to CABG.

Rethinking papillary muscle resection for refractory ventricular tachycardia in the LVAD era. A case report.

We report the case of a 57-year-old man with a history of ischemic cardiomyopathy who presented to the hospital with recurrent episodes of ventricular tachycardia refractory to antiarrhythmic medications. Mapping identified a deep premature ventricular contraction focus in the anterolateral papillary muscle, an area that has been previously identified as difficult to treat with radiofrequency catheter ablation. The hospital course was complicated by cardiogenic shock and VT-storm, and the patient ultimately underwent surgical resection of the anterolateral papillary muscle with left ventricular assist device placement as a successful bridge to cardiac transplantation.

Cardiac Tamponade and Pericardiocentesis: Recognition, Standard Techniques, and Modern Advancements.

Pericardiocentesis is an important diagnostic and therapeutic procedure. In the setting of cardiac tamponade, pericardiocentesis can rapidly improve hemodynamics, and in cases of diagnostic uncertainty, pericardiocentesis allows for fluid analysis to aid in diagnosis. In contemporary practice, the widespread availability of ultrasonography has made echocardiographic guidance the standard of care. Additional tools such as micropuncture technique, live ultrasonographic guidance, and adjunctive tools including fluoroscopy continue to advance and enhance procedural efficiency and safety. When performed by experienced operators, pericardiocentesis is a safe, effective, and potentially life-saving procedure.

Cardiac resynchronisation therapy in anthracycline-induced cardiomyopathy.

INTRODUCTION: Chemotherapy-induced cardiomyopathy has been increasingly recognised as patients are living longer with more effective treatments for their malignancies. Anthracyclines are known to cause left ventricular (LV) dysfunction. While heart failure medications are frequently used, some patients may need consideration for device-based therapies such as cardiac resynchronisation therapy (CRT). However, the role of CRT in anthracycline-induced cardiomyopathy (AIC) is not well understood. METHODS: We performed a retrospective review of all patients undergoing CRT implantation at our centre from 2003 to 2019 with a diagnosis of AIC. The LV remodelling and survival outcomes of this population were obtained and then compared with consecutive patients with other aetiologies of non-ischaemic cardiomyopathy (NICM). RESULTS: A total of 34 patients underwent CRT implantation with a diagnosis of AIC with a mean age of 60.5±12.7 years, left ventricular ejection fraction (LVEF) of 21.7%±7.4%, and 11.3±7.5 years and 10.2±7.4 years from cancer diagnosis and last anthracycline exposure, respectively. At 9.6±8.1 months after CRT implantation, there was an increase of LVEF from 21.8%±7.6% to 30.4%±13.0% (p<0.001). Patients whose LVEF increased by at least 10% post-CRT implant (42.5% of cohort) survived significantly longer than patients who failed to improve their LVEF by that amount (p=0.01). A propensity matched analysis between patients with AIC and 369 consecutive patients with other aetiologies of NICM who underwent CRT implantation during the same period revealed no significant differences in improvement in LVEF or long-term survival. CONCLUSIONS: Patients with AIC undergo LV remodelling with CRT at rates similar to other aetiologies of NICM. Furthermore, AIC post-CRT responders have a favourable long-term mortality compared with non-responders.

Kinetics of generic tacrolimus in heart transplantation: A cautionary note.

Tacrolimus is a core component of immunosuppressive regimens. This study compared active pharmaceutical ingredient (API) and dissolution kinetics of branded tacrolimus and formulations from three generic manufacturers (Mylan, Dr. Reddy's, Intas) including samples from patients who suffered acute cardiac allograft rejection. Generic samples showed similar API content compared to branded samples with no major impurities. Capsules that underwent uniformity testing had consistent capsule-to-capsule API. Dissolution testing showed similar profiles between branded tacrolimus and Mylan, but notable differences with Dr. Reddy's and Intas. The approximate maximal inhibitory concentration (IC50) was highest in branded tacrolimus (29 minutes), followed by Mylan (26 minutes), Dr. Reddy's (19 minutes), and Intas (14 minutes) (Student-Newman-Keuls Multiple Comparisons Test; overall ANOVA: p = 0.0199, F = 6.469). This study suggests that the bioavailability of certain generic tacrolimus formulations peak significantly earlier than branded tacrolimus. Further study is needed to determine whether these differences are clinically relevant.

Effect of High-Dose Zinc and Ascorbic Acid Supplementation vs Usual Care on Symptom Length and Reduction Among Ambulatory Patients With SARS-CoV-2 Infection: The COVID A to Z Randomized Clinical Trial.

Importance: There is limited evidence regarding early treatment of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection to mitigate symptom progression. Objective: To examine whether high-dose zinc and/or high-dose ascorbic acid reduce the severity or duration of symptoms compared with usual care among ambulatory patients with SARS-CoV-2 infection. Design, Setting, and Participants: This multicenter, single health system randomized clinical factorial open-label trial enrolled 214 adult patients with a diagnosis of SARS-CoV-2 infection confirmed with a polymerase chain reaction assay who received outpatient care in sites in Ohio and Florida. The trial was conducted from April 27, 2020, to October 14, 2020. Intervention: Patients were randomized in a 1:1:1:1 allocation ratio to receive either 10 days of zinc gluconate (50 mg), ascorbic acid (8000 mg), both agents, or standard of care. Outcomes: The primary end point was the number of days required to reach a 50% reduction in symptoms, including severity of fever, cough, shortness of breath, and fatigue (rated on a 4-point scale for each symptom). Secondary end points included days required to reach a total symptom severity score of 0, cumulative severity score at day 5, hospitalizations, deaths, adjunctive prescribed medications, and adverse effects of the study supplements. Results: A total of 214 patients were randomized, with a mean (SD) age of 45.2 (14.6) years and 132 (61.7%) women. The study was stopped for a low conditional power for benefit with no significant difference among the 4 groups for the primary end point. Patients who received usual care without supplementation achieved a 50% reduction in symptoms at a mean (SD) of 6.7 (4.4) days compared with 5.5 (3.7) days for the ascorbic acid group, 5.9 (4.9) days for the zinc gluconate group, and 5.5 (3.4) days for the group receiving both (overall P = .45). There was no significant difference in secondary outcomes among the treatment groups. Conclusions and Relevance: In this randomized clinical trial of ambulatory patients diagnosed with SARS-CoV-2 infection, treatment with high-dose zinc gluconate, ascorbic acid, or a combination of the 2 supplements did not significantly decrease the duration of symptoms compared with standard of care. Trial Registration: ClinicalTrials.gov Identifier: NCT04342728.

Blood Pressure Response during Cardiopulmonary Exercise Testing in Heart Failure.

INTRODUCTION: The prognostic value of peak V˙O2 and V˙E/V˙CO2 slope measured during cardiopulmonary exercise (CPX) testing has been well established in patients with advanced heart failure, but blood pressure response to exercise is less well characterized. METHODS: We retrospectively studied 151 outpatients who underwent CPX testing as part of an advanced heart failure evaluation. The outcome of interest was failure of medical management, defined by death, cardiac transplantation, or left ventricular assist device placement. Patients were stratified into tertiles by change in systolic blood pressure (SBP) (<13, 13-26, and ≥27 mm Hg) during exercise. RESULTS: Patients in the lowest tertile had the lowest peak V˙O2 (10.2 vs 10.6 vs 13.6 mL·kg·min, P = <0.001), the highest V˙E/V˙CO2 slope (42.8 vs 42.1 vs 36.3, P = 0.030), the shortest mean exercise time (5.1 vs 6.0 vs 7.0 min, P = <0.001), and the highest probability of failure of medical management at 1.5 yr (0.69 vs 0.41 vs 0.34, P = 0.011). After multivariate adjustment, increased SBP <20 mm Hg during exercise was associated with a lower hazard of medical management failure (hazard ratio = 0.96, 95% confidence interval [CI] = 0.934-0.987), whereas SBP increases >20 mm Hg were associated with an increased hazard (hazard ratio = 1.046, 95% CI = 1.018-1.075). CONCLUSION: In conclusion, changes in SBP during CPX testing provide additional prognostic information above standard clinical variables. The peculiar increase in risk noted in those with a rise in SBP >20 mm Hg is less clear and needs to be investigated further.

Right Ventricular Longitudinal Strain Reproducibility Using Vendor-Dependent and Vendor-Independent Software.

BACKGROUND: Right ventricular peak systolic longitudinal strain (RVLS) has emerged as an approach for quantifying right ventricular function in diseases such as pulmonary hypertension and congenital heart disease. A major limitation in applying RVLS is that strain imaging and analysis are proprietary, which may result in systematic differences from vendor to vendor. The goal of this study was to test the reproducibility of right ventricular strain analysis among selected vendor-specific software (VSS) and vendor-independent software (VIS) on images obtained from different ultrasound scanners, as would be common in clinical practice or in a multicenter clinical trial. METHODS: In this prospective, single-center study, 35 patients (5 healthy subjects and 30 with pulmonary hypertension) each underwent two echocardiographic scans, one using GE (Vivid E9) and the other using Philips (iE33) ultrasound systems. Images were analyzed using both VSS and VIS (TomTec) software for determination of RVLS. A repeated-measures analysis of variance was used to assess for any systematic differences among methods, as well as effects of scanner and software and a possible interaction between scanner and software for each strain measurement. RESULTS: Differences for global strains were not statistically significant among VSS packages (P ≥ .05), but some differences were noted between VSS and VIS. Wide variability between regional peak strain measurements was noted, but no systematic differences were found. CONCLUSIONS: Global RVLS values between VSS systems are not significantly different but may differ slightly from VIS. When comparing regional strain between VSS and VIS analyses, there is widespread variability without clear systematic differences.

Clinical Utility and Prognostic Value of Right Atrial Function in Pulmonary Hypertension.

Background Although right atrial (RA) enlargement is an established marker for adverse outcomes, the prognostic importance of RA dysfunction independent of RA size in pulmonary arterial hypertension is not known. Methods and Results Study subjects with pulmonary arterial hypertension were prospectively enrolled from 2010 to 2014. RA function was measured using RA speckle-tracking longitudinal strain and strain rate (SR) during each phase of the cardiac cycle: (1) RA reservoir (peak longitudinal strain, peak systolic SR), (2) RA conduit (peak early diastolic SR), and (3) RA active contraction (peak active contraction strain, peak contraction SR). The primary outcome was a composite of time to hospitalization or death assessed on follow-up. A total of 63 subjects had complete echocardiographic data. Of these, 91% were females, and the mean age was 58±12 years. During the follow-up period (range: 1-58 months), 39 were hospitalized or had died. After multivariable adjustment for age, sex, and left atrial size, peak longitudinal strain, peak active contraction strain, and peak early diastolic SR were significantly associated with increased risk of the composite outcome ( P=0.0005, P=0.0167, and P=0.0054, respectively). Conclusions RA dysfunction independently predicts mortality and hospitalizations in patients with pulmonary arterial hypertension.

Time-dependence in mixture toxicity prediction.

The value of time-dependent toxicity (TDT) data in predicting mixture toxicity was examined. Single chemical (A and B) and mixture (A+B) toxicity tests using Microtox(®) were conducted with inhibition of bioluminescence (Vibrio fischeri) being quantified after 15, 30 and 45-min of exposure. Single chemical and mixture tests for 25 sham (A1:A2) and 125 true (A:B) combinations had a minimum of seven duplicated concentrations with a duplicated control treatment for each test. Concentration/response (x/y) data were fitted to sigmoid curves using the five-parameter logistic minus one parameter (5PL-1P) function, from which slope, EC25, EC50, EC75, asymmetry, maximum effect, and r(2) values were obtained for each chemical and mixture at each exposure duration. Toxicity data were used to calculate percentage-based TDT values for each individual chemical and mixture of each combination. Predicted TDT values for each mixture were calculated by averaging the TDT values of the individual components and regressed against the observed TDT values obtained in testing, resulting in strong correlations for both sham (r(2)=0.989, n=25) and true mixtures (r(2)=0.944, n=125). Additionally, regression analyses confirmed that observed mixture TDT values calculated for the 50% effect level were somewhat better correlated with predicted mixture TDT values than at the 25 and 75% effect levels. Single chemical and mixture TDT values were classified into five levels in order to discern trends. The results suggested that the ability to predict mixture TDT by averaging the TDT of the single agents was modestly reduced when one agent of the combination had a positive TDT value and the other had a minimal or negative TDT value.

Evaluation of an asymmetry parameter for curve-fitting in single-chemical and mixture toxicity assessment.

In mixture toxicity, concentration-effect data are often used to generate conclusions on combined effect. While models of combined effect are available for such assessments, proper fitting of the data is critical to obtaining accurate conclusions. In this study an asymmetry parameter (s) was evaluated for data-fitting and compared with our previous approach. Inhibition of bioluminescence was assessed with Vibrio fischeri at 15, 30 and 45-min of exposure with seven or eight concentrations and a control (each duplicated) for each single-chemical (A or B) and mixture (A:B). Concentration-effect data were fitted to sigmoid curves using the four-parameter logistic function (4PL) and the five-parameter logistic minus one-parameter (5PL-1P) function. For the 4PL, parameters included minimum effect, maximum effect, EC(50) and slope, while for the 5PL-1P the minimum effect parameter was removed and an asymmetry parameter was added. A total of 72 mixture toxicity data sets were evaluated, representing 432 single-chemical and 216 mixture curves. Mean coefficients of determination (r(2)) for all 648 curves showed that the 5PL-1P gave better fitting (0.9982 ± 0.0018) than the 4PL (0.9973 ± 0.0030). For both functions, the sum-of-squares of the residuals (SS-Res) was determined for each curve. The 5-parameter rational regression best described the relationship between the decrease in sum-of-squares of the residuals (i.e., 4PL: SS-Res - 5PL-1P: SS-Res) and log s, with fitting improved the most at low values of s (s<0.8). This held even when curves with r(2) values ≤ 0.9970 were removed from the analyses. Subsequent review of the combined effects obtained via the 4PL and the 5PL-1P functions resulted in a change in the interpretation of combined effect in 39/216 (18%) cases.