Reduction of left ventricular diastolic pressure as a key regulator of infarct coronary flow under mechanical left ventricular support.

Restoring ischaemic myocardial tissue perfusion is crucial for minimizing infarct size. Acute mechanical left ventricular (LV) support has been suggested to improve infarct tissue perfusion. However, its regulatory mechanism remains unclear. We investigated the physiological mechanisms in six Yorkshire pigs, which were subjected to 90-min balloon occlusion of the left anterior descending artery. During the acute reperfusion phase, LV support using an Impella heart pump was initiated. LV pressure, coronary flow and pressure of the infarct artery were simultaneously recorded to evaluate the impact of LV support on coronary physiology. Coronary wave intensity was calculated to understand the forces regulating coronary flow. Significant increases in coronary flow velocity and its area under the curve were found after mechanical LV support. Among the coronary flow-regulating factors, coronary pressure was increased mainly during the late diastolic phase with less pulsatility. Meanwhile, LV pressure was reduced throughout diastole resulting in significant and consistent elevation of coronary driving pressure. Interestingly, the duration of diastole was prolonged with LV support. In the wave intensity analysis, the duration between backward suction and pushing waves was extended, indicating that earlier myocardial relaxation and delayed contraction contributed to the extension of diastole. In conclusion, mechanical LV support increases infarct coronary flow by extending diastole and augmenting coronary driving pressure. These changes were mainly driven by reduced LV diastolic pressure, indicating that the key regulator of coronary flow under mechanical LV support is downstream of the coronary artery, rather than upstream. Our study highlights the importance of LV diastolic pressure in infarct coronary flow regulation. KEY POINTS: Restoring ischaemic myocardial tissue perfusion is crucial for minimizing infarct size. Although mechanical left ventricular (LV) support has been suggested to improve infarct coronary flow, its specific mechanism remains to be clarified. LV support reduced LV pressure, and elevated coronary pressure during the late diastolic phase, resulting in high coronary driving pressure. This study demonstrated for the first time that mechanical LV support extends diastolic phase, leading to increased infarct coronary flow. Future studies should evaluate the correlation between improved infarct coronary flow and resulting infarct size.

In-hospital outcomes of transcatheter aortic valve replacement in patients with chronic and end-stage renal disease: a nationwide database study.

BACKGROUND: Chronic kidney disease (CKD) and end-stage renal disease (ESRD) have been associated with worse outcomes after transcatheter aortic valve replacement (TAVR). With TAVR indications extending to a wider range of patient populations, it is important to understand the current implications of chronic renal insufficiency on clinical outcomes. We aim to determine the impact of CKD and ESRD on in-hospital outcomes after TAVR. METHODS: We queried the National Inpatient Sample for TAVR performed between 2016 and 2020 using International Classification of Diseases-10th Revision codes. We compared in-hospital mortality and clinical outcomes between three groups: normal renal function, CKD and ESRD. The association between CKD/ESRD and outcomes was tested with multivariable logistic regression analyses, using normal renal function as baseline. RESULTS: In the five-year study period, 279,195 patients underwent TAVR (mean age 78.9 ± 8.5 years, 44.4% female). Of all patients, 67.1% had normal renal function, 29.2% had CKD, and 3.7% had ESRD. There were significant differences in age, sex, and prevalence of comorbidities across groups. In-hospital mortality was 1.3%. Compared to patients with normal renal function, patients with renal insufficiency had higher in-hospital mortality, with the highest risk found in patients with ESRD (adjusted odds ratio: 1.4 [95% confidence interval: 1.2-1.7] for CKD; adjusted odds ratio: 2.4 [95% confidence interval: 1.8-3.3] for ESRD). Patients with CKD or ESRD had a higher risk of cardiogenic shock, need for mechanical circulatory support, and vascular access complications, compared to those with normal renal function. In addition, patients with ESRD had a higher risk of cardiac arrest and periprocedural acute myocardial infarction. The incidence of conversion to open heart surgery was 0.3% and did not differ between groups. Post-procedural infectious and respiratory complications were more common among patients with CKD or ESRD. CONCLUSION: Patients with CKD and ESRD are at higher risk of in-hospital mortality, cardiovascular, and non-cardiovascular complications after TAVR. The risk of complications is highest in patients with ESRD and does not result in more frequent conversion to open heart surgery. These results emphasize the importance of individualized patient selection for TAVR and procedural planning among patients with chronic renal insufficiency.

Impact of ischemia on left atrial remodeling and dysfunction in swine models of mitral regurgitation.

Left atrial (LA) dysfunction is one of the predictive factors of worse outcomes after mitral valve surgery for mitral regurgitation (MR). We aimed to investigate the effect of MR etiology on progression of LA remodeling in swine MR models. MR was induced in 14 Yorkshire pigs using catheter-based procedures. Seven pigs underwent simultaneous occlusions of the left circumflex artery and the diagonal branch, which resulted in ischemic mitral regurgitation (IMR group). The other seven pigs underwent chordal severing to induce leaflet prolapse simulating degenerative mitral regurgitation (DMR group). Changes in LA volume and function were assessed at baseline, 1 mo, and 3 mo using echocardiography and hemodynamic evaluations. Histopathological assessments were conducted to evaluate LA hypertrophy and fibrosis. At 3 mo, quantitative MR severity was comparable and severe in both groups. Despite the similar degree of MR, minimum LA volume index increased significantly more in the IMR group (IMR: 11.9 ± 6.4 to 73.2 ± 6.4 mL/m2, DMR: 10.7 ± 6.4 to 29.5 ± 6.4 mL/m2, Pinteraction = 0.004). Meanwhile, increase in maximum LA volume index was similar between the groups, resulting in lower LA emptying function in the IMR group (IMR: 60.1 ± 3.1 to 29.4 ± 3.1%; DMR: 62.4 ± 3.1 to 58.2 ± 3.1%, Pinteraction = 0.0003). LA reservoir strain assessed by echocardiography was also significantly lower in the IMR group. Histological analyses revealed increased LA cellular hypertrophy and fibrosis in the IMR group. In conclusion, ischemic MR is associated with aggressive remodeling and reduced emptying function compared with the MR due to leaflet prolapse. Earlier intervention might be necessary for ischemic MR to prevent LA remodeling.NEW & NOTEWORTHY We show different LA structural and functional remodeling patterns between ischemic MR and MR due to leaflet prolapse. Severe ischemic MR was accompanied by extensive LA remodeling, which may be associated with poor clinical outcomes. Our data suggest that detailed structural and functional LA remodeling assessment is important for managing IMR and to determine the presence of LA ischemia.

Sarcopenia index as a predictor of clinical outcomes in older patients undergoing transcatheter aortic valve replacement.

BACKGROUND: Sarcopenia is a prevalent condition in elderly patients and has been associated with adverse outcomes following transcatheter aortic valve replacement (TAVR). The present study aimed to determine the predictive value of serum creatinine-cystatin C ratio, that is, "Sarcopenia Index" (SI) as a surrogate marker of sarcopenia, and investigate its association with clinical outcomes after TAVR. METHODS: We conducted a retrospective observational study of patients undergoing TAVR between January, 2016 and December, 2018 at Hospital Italiano de Buenos Aires, Argentina. Patients were excluded if <65-years old, presented previous surgical aortic valve replacement, severe chronic kidney disease, or hemodialysis requirement. The SI was obtained at baseline before TAVR. All-cause mortality and/or readmissions for congestive heart failure (CHF) were defined as the primary endpoint. RESULTS: In total 100 patients met inclusion criteria for the purpose of the study. Sarcopenia Index was significantly correlated with Timed Up and Go (r = -0.272, p = .010) and Gait Speed (r = -0.278, p = .005). During follow-up, 5/100 patients died within 30 days and a total of 10/100 patients died at 1-year follow-up. Moreover, survival curves were significantly worse (Log-rank test = p = .02) and CHF readmissions were more prevalent in the lowest SI tertile (Log-rank test = p = .01). In multivariate Cox regression analysis, we identified low SI (cutoff ≤66) as an independent predictor of long-term adverse outcomes (HR = 4.01, 95% CI = 1.31-12.27, p = .015) at 1-year follow-up. CONCLUSION: Sarcopenia Index, surrogate for the degree of skeletal muscle mass (SMM), could be used as a predictor of adverse outcomes in patients undergoing TAVR.

Additive prognostic value of carbohydrate antigen-125 over frailty in patients undergoing transcatheter aortic valve replacement.

BACKGROUND: To evaluate the additive prognostic value of myocardial, inflammatory, and renal biomarkers according to frailty status in patients undergoing transcatheter aortic valve replacement (TAVR) for aortic stenosis (AS). METHODS: A total of 111 subjects who underwent TAVR at Hospital Italiano de Buenos Aires, Argentina between January 2016 and December 2018 were retrospectively reviewed. Plasma levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP), high sensitivity troponin T (hs-cTnT), C-reactive protein (CRP), cystatin-c (Cys-C) and carbohydrate antigen-125 (CA-125) were assessed prior to TAVR. Frailty status was assessed according to the fried physical frailty phenotype (FPFP). The primary endpoint was defined as all-cause death and/or readmission for worsening congestive heart failure (CHF) within the first year after TAVR. RESULTS: Of the 111 patients included, 48/111 (43%) were considered to be "frail" according to the FPFP. Among biomarkers, we found CA-125 to be strongly associated with the primary endpoint (p = .006). CA-125 ≥ 18.2 U/ml was present in 41% and was associated with a higher rate of the primary endpoint (31% vs. 9%; p = .003). After multivariable adjustment, CA-125 ≥ 18.2 U/ml (hazard ratio [HR] 3.17; p = .024) was the only independent predictor of the primary endpoint. Finally, the inclusion of CA-125 to frailty significantly improved C-index (0.68-0.74; p < .05), and provided a Net Reclassification Improvement (NRI) of 0.34 (95% CI 0.19-0.49, p = .031), largely through reductions in risk estimates among pre-frail and frail patients. CONCLUSIONS: CA-125, a tumor biomarker, outperformed frailty for predicting the primary endpoint within the first year after TAVR.

Role of Colchicine in Cardiovascular Disorders.

Inflammation has played a pivotal role in atherosclerosis and other cardiovascular disorders, prompting the exploration of anti-inflammatory therapies to improve cardiovascular outcomes. Colchicine, a well-established agent in conditions such as gout and familial Mediterranean fever, has emerged as a promising novel anti-inflammatory agent in the realm of cardiovascular diseases. Its ability to target both traditional risk factors and residual inflammatory risk marks a significant advancement in cardiovascular prevention strategies, indicating a new era in cardiovascular care. Landmark trials have supported the efficacy and safety of low-dose colchicine in reducing major adverse cardiovascular events when combined with standard therapies. In addition, its endorsement by major cardiovascular societies underscores its significance as the first targeted anti-inflammatory therapy for cardiovascular disease. However, careful monitoring for drug interactions and adverse effects, particularly on kidney and liver function, is essential for safe use. In this review, we aim to comprehensively summarize the mechanisms of action of colchicine, its molecular and biochemical targets in various cardiovascular conditions, and its pharmacokinetics, and delve deeply into the existing evidence on its safety and efficacy in the treatment of cardiovascular disorders, including coronary artery disease, pericarditis, atrial fibrillation, and heart failure.

Progress in Clinical Gene Therapy for Cardiac Disorders.

Despite significant advances in novel treatments and approaches, cardiovascular disease remains the leading cause of death globally. Gene therapy is a promising option for many diseases, including cardiovascular diseases. In the last 30 years, gene therapy has slowly proceeded towards clinical translation and recently reached US Food and Drug Administration approval for several diseases such as Leber congenital amaurosis and spinal muscular atrophy, among others. Previous attempts at developing gene therapies for cardiovascular diseases have yielded promising results in preclinical studies and early-phase clinical trials. However, larger trials failed to demonstrate consistent benefits in patients with ischemic heart disease and heart failure. In this review, we summarize the history and current status of clinical cardiac gene therapy. Starting with angiogenic gene therapy, we also cover more recent gene therapy trials for heart failure and cardiomyopathies. New programs are actively vying to be the first to get Food and Drug Administration approval for a cardiac gene therapy product by taking advantage of novel techniques.

Elevated Lipoprotein(a) Levels and Atrial Fibrillation: A Systematic Review.

Objective: The role of lipoprotein(a) (Lp[a]) as a possibly causal risk factor for atherosclerotic cardiovascular disease has been well established. However, the clinical evidence regarding the association between Lp(a) levels and atrial fibrillation (AF) remains limited and inconsistent. This study aimed to analyze the association between elevated Lp(a) levels or single-nucleotide polymorphisms (SNPs) related to high levels of Lp(a) and AF. Methods: This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A literature search was performed to identify studies that evaluated the association between Lp(a) levels or SNPs related to high levels of Lp(a) and AF. Observational studies with a cross-sectional, case-control, or cohort design were included in this systematic review, without limitations according to language, country, or publication type. Results: Eleven observational studies including 1,246,817 patients were eligible for this systematic review. Two cross-sectional studies, 5 prospective/retrospective cohort studies, and 4 Mendelian randomization studies were analyzed. Two cross-sectional studies that compared Lp(a) levels between patients with and without AF showed conflicting results. Cohort studies that evaluated the incidence of AF according to Lp(a) levels showed different results: no association (3 studies), a positive association (1 study), and an inverse relationship (1 study). Finally, Mendelian randomization studies also showed heterogeneous results (positive association: 2 studies; inverse association: 1 study; no association: 1 study). Conclusion: Although there could be an association between Lp(a) levels and AF, the results of the studies published to date are contradictory and not yet definitive. Therefore, further research should clarify this issue.

Negative Impact of Acute Reloading after Mechanical Left Ventricular Unloading.

Mechanical LV unloading for acute myocardial infarction (MI) is a promising supportive therapy to reperfusion. However, no data is available on exit strategy. We evaluated hemodynamic and cellular effects of reloading after Impella-mediated LV unloading in Yorkshire pigs. First, we conducted an acute study in normal heart to observe effects of unloading and reloading independent of MI-induced ischemic effects. We then completed an MI study to investigate optimal exit strategy on one-week infarct size, no-reflow area, and LV function with different reloading speeds. Initial studies showed that acute reloading causes an immediate rise in end-diastolic wall stress followed by a significant increase in cardiomyocyte apoptosis. The MI study did not result in any statistically significant findings; however, numerically smaller average infarct size and no-reflow area in the gradual reloading group prompt further examination of reloading approach as an important clinically relevant consideration.

Melatonin Preserves Fluidity in Cell and Mitochondrial Membranes against Hepatic Ischemia-Reperfusion.

We evaluated the in vivo effects of melatonin treatment on oxidative damage in the liver in an experimental model of ischemia-reperfusion. A total of 37 male Sprague-Dawley rats were randomly divided into four groups: control, ischemia, ischemia + reperfusion, and ischemia + reperfusion + melatonin. Hepatic ischemia was maintained for 20 min, and the clamp was removed to initiate vascular reperfusion for 30 min. Melatonin (50 mg/kg body weight) was intraperitoneally administered. Fluidity was measured by polarization changes in 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene-p-toluene sulfonate). After 20 min of ischemia, no significant changes were observed in cell and mitochondrial membrane fluidity levels, lipid peroxidation, and protein carbonylation. However, after 30 min of reperfusion, membrane fluidity decreased compared to controls. Increases in lipid and protein oxidation were also seen in hepatic homogenates of animals exposed to reperfusion. Melatonin injected 30 min before ischemia and reperfusion fully prevented membrane rigidity and both lipid and protein oxidation. Livers from ischemia-reperfusion showed histopathological alterations and positive labeling with antibodies to oxidized lipids and proteins. Melatonin reduced the severity of these morphological changes and protected against in vivo ischemia-reperfusion-induced toxicity in the liver. Therefore, melatonin might be a candidate for co-treatment for patients with hepatic vascular occlusion followed by reperfusion.

Updates on Cardiac Gene Therapy Research and Methods: Overview of Cardiac Gene Therapy.

Gene therapy has made a significant progress in clinical translation over the past few years with several gene therapy products currently approved or anticipating approval for clinical use. Cardiac gene therapy lags behind that of other areas of diseases, with no application of cardiac gene therapy yet approved for clinical use. However, several clinical trials for gene therapy targeting the heart are underway, and innovative research studies are being conducted to close the gap. The second edition of Cardiac Gene Therapy in Methods in Molecular Biology provides protocols for cutting-edge methodologies used in these studies. In this chapter, we discuss recent updates on cardiac gene therapy studies and provide an overview of the chapters in the book.

Device-Based Approaches Targeting Cardioprotection in Myocardial Infarction: The Expanding Armamentarium of Innovative Strategies.

Coronary reperfusion therapy has played a pivotal role for reducing mortality and heart failure after acute myocardial infarction. Although several adjunctive approaches have been studied for reducing infarct size further, both ischemia-reperfusion injury and microvascular obstruction are still major contributors to both early and late clinical events after acute myocardial infarction. The progress in the field of cardioprotection has found several promising proof-of-concept preclinical studies. However, translation from bench to bedside has not been very successful. This comprehensive review discusses the importance of infarct size as a driver of clinical outcomes post-acute myocardial infarction and summarizes recent novel device-based approaches for infarct size reduction. Device-based interventions including mechanical cardiac unloading, myocardial cooling, coronary sinus interventions, supersaturated oxygen therapy, and vagal stimulation are discussed. Many of these approaches can modify ischemic myocardial biology before reperfusion and offer unique opportunities to target ischemia-reperfusion injury.

Assessing the Effect of Cardiac Gene Therapy Using Catheter-Based Pressure-Volume Measurement in Large Animals.

Gene therapy for heart failure targets various pathways that modulate cardiac function. Its detailed evaluation is crucial for proving the efficacy of cardiac gene therapies. Parameters that can be obtained by noninvasive approaches are generally influenced by loading conditions of the heart. In contrast, catheter-based left ventricular pressure-volume assessment provides a unique option to minimally invasively assess intrinsic myocardial function in a load-insensitive manner. In this chapter, we describe procedural steps for performing pressure-volume measurements and analysis in a preclinical large animal model.

Severe Obesity and Heart Failure.

Obesity is associated with reduced mortality in some patients hospitalized for heart failure (HF). In this analysis, we determine if this nonlinear relation, referred to as the obesity paradox, extends to secondary outcomes in patients diagnosed with severe obesity. This is a retrospective cohort study using the 2017 and 2018 National Inpatient Sample that includes adults hospitalized for HF. Patients with diagnosis codes specifying severe obesity, nonsevere obesity, or without obesity are compared. The primary outcome is mortality. Secondary outcomes include the length of stay (LOS), total charges, and cardiogenic shock (CS). Multivariate regression is used to adjust for demographics and co-morbidities. A total of 2,439,845 hospitalizations are included. A decreased mortality is found in nonsevere obesity (odds ratio 0.74, 95% confidence interval 0.69 to 0.80, p = 0.000), affirming the obesity paradox. However, this decreased mortality is not found in severe obesity (odds ratio 1.01, 95% confidence interval 0.94 to 1.08, p = 0.766). Severe obesity and nonsevere obesity are also associated with less CS and increased LOS compared with non-obese patients. Severe obesity is associated with increased total charges. In conclusion, a nonlinear, U-shaped relation between obesity and mortality in patients hospitalized for HF is demonstrated, where those not obese and those severely obese experience greater mortality compared with the nonseverely obese. However, for secondary outcomes of CS, LOS, and total charges, the relation is linear and therefore not interpreted as paradoxical. More information is needed using the adiposity-based chronic disease model to characterize complex relations between obesity and mortality.

Comparison of Different Stenting Techniques in Left Main Bifurcation Disease: Evidence From a Network Meta-Analysis.

OBJECTIVES: We aimed to assess which bifurcation technique performs best in unprotected left-main (LM) percutaneous coronary intervention (PCI). BACKGROUND: Provisional stenting was considered the preferred technique for LM bifurcation PCI due to the supposed lower risks of thrombosis and restenosis. However, recent studies showed potential advantages of double kissing (DK)-crush technique over the other strategies. METHODS: We performed a frequentist network meta-analysis comparing different stenting techniques in the setting of LM bifurcation. PubMed, Embase, the Cochrane Central Register of Controlled Trials, and Clinicaltrials.gov were searched. Both randomized clinical trials and non-randomized clinical trials were considered eligible for inclusion. Incidence rate ratios (IRRs) were computed using a random-effects model for death, cardiac death, myocardial infarction, target-vessel revascularization, target-lesion revascularization, and stent thrombosis, including 95% confidence intervals (CIs). RESULTS: A total of 10 studies (2364 patients) were included. Compared with provisional stenting, DK-crush was associated with fewer cardiac deaths (IRR, 0.34; 95% CI, 0.17-0.70; P<.01), myocardial infarctions (IRR, 0.19; 95% CI, 0.08-0.44; P<.001), stent thromboses (IRR, 0.31; 95% CI, 0.14-0.69; P<.01), target-vessel revascularizations (IRR, 0.25; 95% CI, 0.14-0.46; P<.001), and target-lesion revascularizations (IRR, 0.25; 95% CI, 0.14-0.46; P<.001). DK-crush was also associated with a lower risk of myocardial infarction (IRR, 0.19; 95% CI, 0.05-0.76; P=.02) when compared with standard crush and lower risk of target-lesion revascularization when compared with culotte (IRR, 0.32; 95% CI, 0.12-0.83; P=.02) and crush (IRR, 0.07; 95% CI, 0.02-0.28; P<.001). CONCLUSIONS: DK-crush is the best technique for unprotected LM bifurcation PCI.

Impaired Diastolic Function Predicts Improved Ischemic Myocardial Flow by Mechanical Left Ventricular Unloading in a Swine Model of Ischemic Heart Failure.

Background: Impact of mechanical left ventricular (LV) unloading on myocardial tissue perfusion and its regulating factors remain unclear. This study was conducted to elucidate the predictors of regional blood flow (RBF) improvement by mechanical LV unloading. Materials and Methods: One to four weeks after percutaneous induction of myocardial infarction (MI), Yorkshire pigs (n = 15) underwent mechanical LV unloading using Impella CP. Hemodynamic parameters were collected prior to LV unloading. RBF in infarct, border and remote myocardium were measured by fluorescent microsphere injections before and 120 min after LV unloading. Results: RBF showed variable responses to mechanical LV unloading. While infarct RBF improved in general (0.33 ± 0.13 to 0.42 ± 0.19 mL/min/g, p = 0.06), there were a few pigs that showed little improvement. Meanwhile, there were no clear trends in the border (1.07 ± 0.47 to 1.02 ± 0.65 mL/min/g, p = 0.73) and remote myocardial RBF (1.25 ± 0.52 to 1.23 ± 0.68 mL/min/g, p = 0.85). In the simple linear regression analysis, cardiac output, mean pulmonary arterial wedge pressure, mean left atrial pressure, minimum LV pressure, end-diastolic LV pressure, maximum dP/dt, slope of end-diastolic pressure-volume relationship (EDPVR) and end-diastolic wall stress were significantly associated with % change of infarct RBF. In the multiple regression model, slope of EDPVR and maximum dP/dt remained as independent predictors of infarct RBF change. Conclusion: Steeper EDPVR and lower maximum dP/dt were associated with increased blood perfusion in the infarct area after LV unloading. Our data suggests mechanical LV unloading is more beneficial in post-MI patients with high diastolic pressure associated with increased LV stiffness and in those with worse cardiac contractility.

Therapeutic angiogenesis in coronary artery disease: a review of mechanisms and current approaches.

INTRODUCTION: Despite tremendous advances, the shortcomings of current therapies for coronary disease are evidenced by the fact that it remains the leading cause of death in many parts of the world. There is hence a drive to develop novel therapies to tackle this disease. Therapeutic approaches to coronary angiogenesis have long been an area of interest in lieu of its incredible, albeit unrealized potential. AREAS COVERED: This paper offers an overview of mechanisms of native angiogenesis and a description of angiogenic growth factors. It progresses to outline the advances in gene and stem cell therapy and provides a brief description of other investigational approaches to promote angiogenesis. Finally, the hurdles and limitations unique to this particular area of study are discussed. EXPERT OPINION: An effective, sustained, and safe therapeutic option for angiogenesis truly could be the paradigm shift for cardiovascular medicine. Unfortunately, clinically meaningful therapeutic options remain elusive because promising animal studies have not been replicated in human trials. The sheer complexity of this process means that numerous major hurdles remain before therapeutic angiogenesis truly makes its way from the bench to the bedside.