Localization of coronary bypass targets in hard-to-see coronary arteries

BACKGROUND

Precise identification of coronary arteries and selection of anastomotic sites are critical stages of coronary bypass surgery. Visualization of coronary arteries is occasionally challenging when the heart is covered with a thick layer of fat or scar tissue. In this paper, we review the methods to localize the coronary arteries during coronary surgery.

METHODS

Prior publications were searched to summarize all available methods for localization of coronary arteries during coronary surgery.

RESULTS

Five clinically recognized and three experimental techniques from the literature review are reviewed and summarized.

CONCLUSIONS

Knowledge of various techniques of coronary artery identification in hard-to-see coronary arteries is an important asset in coronary surgery and especially useful during the most critical option of the most common heart surgery.

Association Between Early Left Ventricular Ejection Fraction Improvement After Transcatheter Aortic Valve Replacement and 5-Year Clinical Outcomes

Importance

In patients with severe aortic stenosis and left ventricular ejection fraction (LVEF) less than 50%, early LVEF improvement after transcatheter aortic valve replacement (TAVR) is associated with improved 1-year mortality; however, its association with long-term clinical outcomes is not known.

Objective

To examine the association between early LVEF improvement after TAVR and 5-year outcomes.

Design, Setting, and Participants

This cohort study analyzed patients enrolled in the Placement of Aortic Transcatheter Valves (PARTNER) 1, 2, and S3 trials and registries between July 2007 and April 2015. High- and intermediate-risk patients with baseline LVEF less than 50% who underwent transfemoral TAVR were included in the current study. Data were analyzed from August 2020 to May 2021.

Exposures

Early LVEF improvement, defined as increase of 10 percentage points or more at 30 days and also as a continuous variable (ΔLVEF between baseline and 30 days).

Main Outcomes and Measures

All-cause death at 5 years.

Results

Among 659 included patients with LVEF less than 50%, 468 (71.0%) were male, and the mean (SD) age was 82.4 (7.7) years. LVEF improvement within 30 days following transfemoral TAVR occurred in 216 patients (32.8%) (mean [SD] ΔLVEF, 16.4 [5.7%]). Prior myocardial infarction, diabetes, cancer, higher baseline LVEF, larger left ventricular end-diastolic diameter, and larger aortic valve area were independently associated with lower likelihood of LVEF improvement. Patients with vs without early LVEF improvement after TAVR had lower 5-year all-cause death (102 [50.0%; 95% CI, 43.3-57.1] vs 246 [58.4%; 95% CI, 53.6-63.2]; P = .04) and cardiac death (52 [29.5%; 95% CI, 23.2-37.1] vs 135 [38.1%; 95% CI, 33.1-43.6]; P = .05). In multivariable analyses, early improvement in LVEF (modeled as a continuous variable) was associated with lower 5-year all-cause death (adjusted hazard ratio per 5% increase in LVEF, 0.94 [95% CI, 0.88-1.00]; P = .04) and cardiac death (adjusted hazard ratio per 5% increase in LVEF, 0.90 [95% CI, 0.82-0.98]; P = .02) after TAVR. Restricted cubic spline analysis demonstrated a visual inflection point at ΔLVEF of 10% beyond which there was a steep decline in all-cause mortality with increasing degree of LVEF improvement. There were no statistically significant differences in rehospitalization, New York Heart Association functional class, or Kansas City Cardiomyopathy Questionnaire Overall Summary score at 5 years in patients with vs without early LVEF improvement. In subgroup analysis, the association between early LVEF improvement and 5-year all-cause death was consistent regardless of the presence or absence of coronary artery disease or prior myocardial infarction.

Conclusions and Relevance

In patients with severe aortic stenosis and LVEF less than 50%, 1 in 3 experience LVEF improvement within 1 month after TAVR. Early LVEF improvement is associated with lower 5-year all-cause and cardiac death.

Beware of an anomalous left circumflex artery when considering aortic valve or root procedures

Anomalous coronary arteries pose an additional challenge when contemplating surgical options for a patient with aortic valve or root pathology. We demonstrate the course of an anomalous retro-aortic left circumflex coronary artery arising from the right coronary sinus in a patient with an aortic root and ascending aortic aneurysm with severe aortic regurgitation who underwent ascending aorta and aortic valve replacements.

The Role of Angiogenesis and Arteriogenesisin Myocardial Infarction and Coronary Revascularization

Surgical myocardial revascularization is associated with long-term survival benefit in patients with multivessel coronary artery disease. However, the exact biological mechanisms underlying the clinical benefits of myocardial revascularization have not been elucidated yet. Angiogenesis and arteriogenesis biologically leading to vascular collateralization are considered one of the endogenous mechanisms to preserve myocardial viability during ischemia, and the presence of coronary collateralization has been regarded as one of the predictors of long-term survival in patients with coronary artery disease (CAD). Some experimental studies and indirect clinical evidence on chronic CAD confirmed an angiogenetic response induced by myocardial revascularization and suggested that revascularization procedures could constitute an angiogenetic trigger per se. In this review, the clinical and basic science evidence regarding arteriogenesis and angiogenesis in both CAD and coronary revascularization is analyzed with the aim to better elucidate their significance in the clinical arena and potential therapeutic use.

Relation of Subacute Kidney Injury to Mortality After Transcatheter Aortic Valve Implantation

Acute kidney injury after transcatheter aortic valve implantation (TAVI) has been associated with adverse outcomes; however, data are limited on the subacute changes in renal function that occur after discharge and their impact on clinical outcomes. This study investigates the relation between subacute changes in kidney function at 30 days after TAVI and survival. Patients from 2 centers who underwent TAVI and survived beyond 30 days with baseline, in-hospital, and 30-day measures of renal function were retrospectively analyzed. Patients were stratified based on change in estimated glomerular filtration rate (eGFR) from baseline to 30 days as follows: improved (≥15% higher than baseline), worsened (≤15% lower), or unchanged (values in between). Univariable and multivariable models were constructed to identify predictors of subacute changes in renal function and of 2-year mortality. Of the 492 patients who met inclusion criteria, eGFR worsened in 102 (22%), improved in 110 (22%), and was unchanged in 280 (56%). AKI occurred in 90 patients (18%) and in only 27% of patients with worsened eGFR at 30 days. After statistical adjustment, worsened eGFR at 30 days (hazard ratio vs unchanged eGFR 2.09, 95% CI 1.37 to 3.19, p <0.001) was associated with worse survival, whereas improvement in renal function was not associated with survival (hazard ratio vs unchanged eGFR 1.30, 95% CI 0.79 to 2.11, p = 0.30). Worsened renal function at 30 days after TAVI is associated with increased mortality after TAVI. In conclusion, monitoring renal function after discharge may identify patients at high risk of adverse outcomes.

Association of Pulmonary Hypertension With Clinical Outcomes of Transcatheter Mitral Valve Repair

Importance

Pulmonary hypertension (pHTN) is associated with increased risk of mortality after mitral valve surgery for mitral regurgitation. However, its association with clinical outcomes in patients undergoing transcatheter mitral valve repair (TMVr) with a commercially available system (MitraClip) is unknown.

Objective

To assess the association of pHTN with readmissions for heart failure and 1-year all-cause mortality after TMVr.

Design, Setting, and Participants

This retrospective cohort study analyzed 4071 patients who underwent TMVr with the MitraClip system from November 4, 2013, through March 31, 2017, across 232 US sites in the Society of Thoracic Surgery/American College of Cardiology Transcatheter Valve Therapy registry. Patients were stratified into the following 4 groups based on invasive mean pulmonary arterial pressure (mPAP): 1103 with no pHTN (mPAP, <25 mm Hg [group 1]); 1399 with mild pHTN (mPAP, 25-34 mm Hg [group 2]); 1011 with moderate pHTN (mPAP, 35-44 mm Hg [group 3]); and 558 with severe pHTN (mPAP, ≥45 mm Hg [group 4]). Data were analyzed from November 4, 2013, through March 31, 2017.

Interventions

Patients were stratified into groups before TMVr, and clinical outcomes were assessed at 1 year after intervention.

Main Outcomes and Measures

Primary end point was a composite of 1-year mortality and readmissions for heart failure. Secondary end points were 30-day and 1-year mortality and readmissions for heart failure. Linkage to Centers for Medicare & Medicaid Services administrative claims was performed to assess 1-year outcomes in 2381 patients.

Results

Among the 4071 patients included in the analysis, the median age was 81 years (interquartile range, 73-86 years); 1885 (46.3%) were women and 2186 (53.7%) were men. The composite rate of 1-year mortality and readmissions for heart failure was 33.6% (95% CI, 31.6%-35.7%), which was higher in those with pHTN (27.8% [95% CI, 24.2%-31.5%] in group 1, 32.4% [95% CI, 29.0%-35.8%] in group 2, 36.0% [95% CI, 31.8%-40.2%] in group 3, and 45.2% [95% CI, 39.1%-51.0%] in group 4; P < .001). Similarly, 1-year mortality (16.3% [95% CI, 13.4%-19.5%] in group 1, 19.8% [95% CI, 17.0%-22.8%] in group 2, 22.4% [95% CI, 18.8%-26.1%] in group 3, and 27.8% [95% CI, 22.6%-33.3%] in group 4; P < .001) increased across pHTN groups. The association of pHTN with mortality persisted despite multivariable adjustment (hazard ratio per 5-mm Hg mPAP increase, 1.05; 95% CI, 1.01-1.09; P = .02).

Conclusions and Relevance

These findings suggest that pHTN is associated with increased mortality and readmission for heart failure in patients undergoing TMVr using the MitraClip system for severe mitral regurgitation. Further efforts are needed to determine whether earlier intervention before pHTN develops will improve clinical outcomes.

Surgical timing in infective endocarditis complicated by intracranial hemorrhage

Given the growing incidence of infective endocarditis (IE), understanding the risks and benefits of valvular surgery is critical. This decision is particularly complex for the 1 in 10 cases complicated by intracranial hemorrhage (ICH). While guideline recommendations currently favor early surgery in general, delayed intervention of at least 4 weeks is still recommended for patients with ICH. To date, there are no randomized controlled trials that inform management of patients with an indication for surgery but concomitant ICH, and even reported observational data are rare. This paper reviews the current literature on timing of surgery with a specific focus on cases of ICH. It emphasizes a growing body of literature challenging the current paradigm that surgery within 4 weeks is associated with neurologic deterioration and high mortality rates by demonstrating favorable outcomes for patients with pre-operative ICH who undergo early valvular surgery. Based on these data, we propose a practical management algorithm to facilitate decisions on surgical timing in these complicated cases. Since more rigorous evidence may never be available, clinicians should make patient-specific surgical timing decisions that attempt to balance the competing risks of neurologic versus cardiac complications.

Common Coding Variants in SCN10A Are Associated With the Nav1.8 Late Current and Cardiac Conduction

BACKGROUND

Genetic variants at the SCN5A/SCN10A locus are strongly associated with electrocardiographic PR and QRS intervals. While SCN5A is the canonical cardiac sodium channel gene, the role of SCN10A in cardiac conduction is less well characterized.

METHODS

We sequenced the SCN10A locus in 3699 European-ancestry individuals to identify variants associated with cardiac conduction, and replicated our findings in 21,000 individuals of European ancestry. We examined association with expression in human atrial tissue. We explored the biophysical effect of variation on channel function using cellular electrophysiology.

RESULTS

We identified 2 intronic single nucleotide polymorphisms in high linkage disequilibrium (r  ²=0.86) with each other to be the strongest signals for PR (rs10428132, β=-4.74, P=1.52×10^-14) and QRS intervals (rs6599251, QRS β=-0.73; P=1.2×10^-4), respectively. Although these variants were not associated with SCN5A or SCN10A expression in human atrial tissue (n=490), they were in high linkage disequilibrium (r  ²≥0.72) with a common SCN10A missense variant, rs6795970 (V1073A). In total, we identified 7 missense variants, 4 of which (I962V, P1045T, V1073A, and L1092P) were associated with cardiac conduction. These 4 missense variants cluster in the cytoplasmic linker of the second and third domains of the SCN10A protein and together form 6 common haplotypes. Using cellular electrophysiology, we found that haplotypes associated with shorter PR intervals had a significantly larger percentage of late current compared with wild-type (I962V+V1073A+L1092P, 20.2±3.3%, P=0.03, and I962V+V1073A, 22.4±0.8%, P=0.0004 versus wild-type 11.7±1.6%), and the haplotype associated with the longest PR interval had a significantly smaller late current percentage (P1045T, 6.4±1.2%, P=0.03).

CONCLUSIONS

Our findings suggest an association between genetic variation in SCN10A, the late sodium current, and alterations in cardiac conduction.

Clinical Correlates and Prognostic Value of Elevated Right Atrial Pressure in Patients With Hypertrophic Cardiomyopathy

BACKGROUND

The clinical characteristics associated with elevated right atrial pressure (RAP) in hypertrophic cardiomyopathy (HCM) are unknown. Few data exist as to whether elevated RAP has prognostic implications in patients with HCM. This study investigated the clinical correlates and prognostic value of elevated RAP in HCM.Methods and Results:This retrospective cohort study was performed on 180 patients with HCM who underwent right heart catheterization between 1997 and 2014. Elevated RAP was defined as >8 mmHg. Baseline characteristics, mean pulmonary artery pressure, and mean pulmonary capillary wedge pressure (PCWP) were assessed for association with elevated RAP. The predictive value of elevated RAP for all-cause mortality and the development of atrial fibrillation (AF), ventricular tachycardia/fibrillation (VT/VF), and stroke was evaluated. Elevated RAP was associated with higher New York Heart Association class, dyspnea on exertion, orthopnea, edema, jugular venous distention, larger left atrial size, right ventricular hypertrophy, higher pulmonary artery pressure, and higher PCWP. RAP independently predicted all-cause mortality (adjusted hazard ratio [aHR] 2.18 per 5-mmHg increase, 95% confidence interval [CI] 1.05-4.50, P=0.04) and incident AF (aHR 1.85 per 5-mmHg increase, 95% CI 1.20-2.85, P=0.005). Elevated RAP did not predict VT/VF (P=0.36) or stroke (P=0.28).

CONCLUSIONS

Elevated RAP in patients with HCM is associated with left-sided heart failure and is an independent predictor of all-cause mortality and new-onset AF.

Quantifying the learning curve for pulmonary thromboendarterectomy

BACKGROUND

Pulmonary thromboendarterectomy (PTE) is an effective treatment for chronic thromboembolic pulmonary hypertension (CTEPH), but is a technically challenging operation for cardiothoracic surgeons. Starting a new program allows an opportunity to define a learning curve for PTE.

METHODS

A retrospective case review was performed of 134 consecutive PTEs performed from 1998 to 2016 at a single institution. Outcomes were compared using either a two-tailed t-test for continuous variables or a chi-squared test for categorical variables according to experience of the program by terciles (T).

RESULTS

The 30-day mortality was 3.7%. The mean length of hospital stay, length of ICU stay, and duration on a ventilator were 12.6 days, 4.6 days, and 2.0 days, respectively. The mean decrease in systolic pulmonary artery pressure (sPAP) was 41.3 mmHg. Patients with Jamieson type 2 disease had a greater change in mean sPAP than those with type 3 disease (p = 0.039). The mean cardiopulmonary bypass time was 180 min (T1-198 min, T3-159 min, p = <0.001), and the mean circulatory arrest time was 37 min (T1-44 min, T3-31 min, p < 0.001). Plotting circulatory arrest times as a running sum compared to the mean demonstrated 2 inflection points, the first at 22 cases and the second at 95 cases.

CONCLUSIONS

PTE is a challenging procedure to learn, and good outcomes are a result of a multi-disciplinary effort to optimize case selection, operative performance, and postoperative care. Approximately 20 cases are needed to become proficient in PTE, and nearly 100 cases are required for more efficient clearing of obstructed pulmonary arteries.

A 57-Year-Old Man With Insidious Dyspnea and Nonpleuritic Chest and Back Pain

A 57-year-old man with a history of DVT and pulmonary embolism, transient ischemic attacks, prior 60 pack-year smoking history, and oxygen-dependent COPD presented with insidiously worsening dyspnea associated with new pleuritic chest and back pain.

Metabolite Profiles Predict Acute Kidney Injury and Mortality in Patients Undergoing Transcatheter Aortic Valve Replacement

Background

Acute kidney injury (AKI) occurs commonly after transcatheter aortic valve replacement (TAVR) and is associated with markedly increased postoperative mortality. We previously identified plasma metabolites predictive of incident chronic kidney disease, but whether metabolite profiles can identify those at risk of AKI is unknown.

Methods and Results

We performed liquid chromatography–mass spectrometry–based metabolite profiling on plasma from patients undergoing TAVR and subjects from the community‐based Framingham Heart Study (N=2164). AKI was defined by using the Valve Academic Research Consortium‐2 criteria. Of 44 patients (mean age 82±9 years, 52% female) undergoing TAVR, 22 (50%) had chronic kidney disease and 9 (20%) developed AKI. Of 85 metabolites profiled, we detected markedly concordant cross‐sectional metabolic changes associated with chronic kidney disease in the hospital‐based TAVR and Framingham Heart Study cohorts. Baseline levels of 5‐adenosylhomocysteine predicted AKI after TAVR, despite adjustment for baseline glomerular filtration rate (odds ratio per 1‐SD increase 5.97, 95% CI 1.62–22.0; P=0.007). Of the patients who had AKI, 6 (66.7%) subsequently died, compared with 3 (8.6%) deaths among those patients who did not develop AKI (P=0.0008) over a median follow‐up of 7.8 months. 5‐adenosylhomocysteine was predictive of all‐cause mortality after TAVR (hazard ratio per 1‐SD increase 2.96, 95% CI 1.33–6.58; P=0.008), independent of baseline glomerular filtration rate.

Conclusions

In an elderly population with severe aortic stenosis undergoing TAVR, metabolite profiling improves the prediction of AKI. Given the multifactorial nature of AKI after TAVR, metabolite profiles may identify those patients with reduced renal reserve.

Efficacy of polymer injection for ischemic mitral regurgitation: persistent reduction of mitral regurgitation and attenuation of left ventricular remodeling

OBJECTIVES

The aim of this study was to examine the chronic effects of polyvinyl-alcohol (PVA) injection on mitral regurgitation (MR) reduction, mitral valve geometry, and left ventricular (LV) remodeling in a chronic ischemic MR sheep model.

BACKGROUND

Previous studies have demonstrated acute efficacy of PVA hydrogel polymer injection into infarcted myocardium underlying the papillary muscle to relieve MR by papillary muscle repositioning. However, the chronic efficacy of PVA injection in the chronic infarction setting remains unclear.

METHODS

Sixteen sheep developed chronic MR 8 weeks after induced inferoposterior myocardial infarction. Ten consecutive sheep underwent PVA injection (PVA group) and 6 sheep served as control subjects with saline injection. Epicardial 2-/3-dimensional echocardiography was performed at the baseline, chronic MR (pre-injection), and sacrifice (8 weeks after injection) stages.

RESULTS

Both groups were comparable at the baseline and chronic MR stages. At sacrifice, MR decreased from moderate to trace or mild (vena contracta: 0.17 ± 0.08 cm vs. 0.56 ± 0.10 cm, p < 0.001) in the PVA group but progressed to moderate to severe in the control group. End-systolic and -diastolic volumes remained stable in the PVA group but increased significantly in the control group (both p < 0.05). At sacrifice, compared with the control group, the PVA group had significantly less left ventricular remodeling (end-systolic volume: 41.1 ± 10.4 ml vs. 55.9 ± 12.4 ml, p < 0.05), lower MR severity (vena contracta: 0.17 ± 0.08 cm vs. 0.60 ± 0.14 cm, p < 0.01), and favorable changes in mitral valve geometry.

CONCLUSIONS

Polymer injection in a chronic ischemic MR model results in persistent reduction of MR and attenuation of continued left ventricular remodeling over 8 weeks of follow-up.

Late repair of ischemic mitral regurgitation does not prevent left ventricular remodeling: importance of timing for beneficial repair

BACKGROUND

Ischemic mitral regurgitation (MR) is a frequent complication of myocardial infarction associated with left ventricular (LV) dilatation and dysfunction, which doubles mortality. At the molecular level, moderate ischemic MR is characterized by a biphasic response, with initial compensatory rise in prohypertrophic and antiapoptotic signals, followed by their exhaustion. We have shown that early MR repair 30 days after myocardial infarction is associated with LV reverse remodeling. It is not known whether MR repair performed after the exhaustion of compensatory mechanisms is also beneficial. We hypothesized that late repair will not result in LV reverse remodeling.

METHODS AND RESULTS

Twelve sheep underwent distal left anterior descending coronary artery ligation to create apical myocardial infarction and implantation of an LV-to-left atrium shunt to create standardized moderate volume overload. At 90 days, animals were randomized to shunt closure (late repair) versus sham (no repair). LV remodeling was assessed by 3-dimensional echocardiography, dP/dt, preload-recruitable stroke work, and myocardial biopsies. At 90 days, animals had moderate volume overload, LV dilatation, and reduced ejection fraction (all P<0.01 versus baseline, P=NS between groups). Shunt closure at 90 days corrected the volume overload (regurgitant fraction 6 ± 5% versus 27 ± 16% for late repair versus sham, P<0.01) but was not associated with changes in LV volumes (end-diastolic volume 106 ± 15 versus 110 ± 22 mL; end-systolic volume 35 ± 6 versus 36 ± 6 mL) or increases in preload-recruitable stroke work (41 ± 7 versus 39 ± 13 mL mm Hg) or dP/dt (803 ± 210 versus 732 ± 194 mm Hg/s) at 135 days (all P=NS). Activated Akt, central in the hypertrophic process, and signal transducer and activator of transcription 3 (STAT3), a critical node in the hypertrophic stimulus by cytokines, were equally depressed in both groups.

CONCLUSIONS

Late correction of moderate volume overload after myocardial infarction did not improve LV volume or contractility. Upregulation of prohypertrophic intracellular pathways was not observed. This contrasts with previously reported study in which early repair (30 days) reversed LV remodeling. This suggests a window of opportunity to repair ischemic MR after which no beneficial effect on LV is observed, despite successful repair.

Right ventricular failure after cardiac surgery

Right ventricular (RV) failure remains a major problem in cardiac surgery, particularly in the setting of heart transplantation and following institution of left ventricular support. Experimental studies have shown that RV function is derived from 2 sources: the free wall of the RV and the interventricular septum. Management of RV failure involves not only decreasing RV afterload, but also optimizing both contributions to RV function, which is best achieved by optimizing developed systemic pressure. Techniques for managing the pulmonary circulation and strategies for optimizing RV function in various clinical settings are presented.

Risk stratification for sudden cardiac death after septal myectomy

Background

The importance of risk stratification for sudden cardiac death (SCD) after septal myectomy for hypertrophic obstructive cardiomyopathy (HOCM) has not been emphasized previously.

Methods and results

We report 2 patients with SCD or ventricular tachycardia (VT) after septal myectomy for HOCM in whom risk factors for SCD were identified following surgical myectomy. One received an implantable cardioverter-defibrillator (ICD), which subsequently provided appropriate discharges for VT. The other delayed ICD implantation and suffered SCD.

Conclusion

These cases emphasize the importance of risk stratification for SCD after septal myectomy for HOCM.

Polymer injection therapy to reverse remodel the papillary muscles: efficacy in reducing mitral regurgitation in a chronic ischemic model

BACKGROUND

Ischemic mitral regurgitation (MR) results from displacement of the papillary muscles caused by ischemic ventricular distortion. Progressive left ventricular (LV) remodeling has challenged therapy. Our hypothesis is that repositioning of the papillary muscles can be achieved by injection of polyvinyl-alcohol (PVA) hydrogel polymer into the myocardium in chronic MR despite advanced LV remodeling.

METHODS AND RESULTS

Ten sheep underwent ligation of the circumflex branches to produce chronic ischemic MR over 8 weeks. PVA was injected into the myocardium underlying the infarcted papillary muscle. Two-dimensional and 3D echocardiograms and hemodynamic data were obtained before infarct (baseline), before PVA (chronic MR), and after PVA. PVA injection significantly decreased MR from moderate to severe to trace (MR vena contracta, 5.8±1.2 to1.8±1.3 mm; chronic MR to post-PVA stage; P=0.0003). This was associated with a decrease in infarcted papillary muscle-to-mitral annulus tethering distance (30.3±5.7 to 25.9±4.6 mm, P=0.02), tenting volume (1.8±0.7 to 1.4±0.5 mL, P=0.01), and leaflet closure area (8.8±1.3 cm(2)to 7.6±1.3 cm(2), P=0.004) from chronic MR to post-PVA stages. PVA was not associated with significant decreases in LV ejection fraction (41±3% versus 40±3%, P=NS), end-systolic elastance, τ (82±36 ms to 72±26, P=NS), or LV stiffness coefficient (0.05±0.04 to 0.03±0.01).

CONCLUSIONS

PVA hydrogel injections improve coaptation and reduce remodeling in chronic MR without impairing LV systolic and diastolic function. This new approach offers a potential alternative for relieving tethering and ischemic MR by correcting papillary muscle position.

Gene delivery of sarcoplasmic reticulum calcium ATPase inhibits ventricular remodeling in ischemic mitral regurgitation

BACKGROUND

Mitral regurgitation (MR) doubles mortality after myocardial infarction (MI). We have demonstrated that MR worsens remodeling after MI and that early correction reverses remodeling. Sarcoplasmic reticulum Ca(+2)-ATPase (SERCA2a) is downregulated in this process. We hypothesized that upregulating SERCA2a might inhibit remodeling in a surgical model of apical MI (no intrinsic MR) with independent MR-type flow.

METHODS AND RESULTS

In 12 sheep, percutaneous gene delivery was performed by using a validated protocol to perfuse both the left anterior descending and circumflex coronary arteries with occlusion of venous drainage. We administered adeno-associated virus 6 (AAV6) carrying SERCA2a under a Cytomegalovirus promoter control in 6 sheep and a reporter gene in 6 controls. After 2 weeks, a standardized apical MI was created, and a shunt was implanted between the left ventricle and left atrium, producing regurgitant fractions of ≈30%. Animals were compared at baseline and 1 and 3 months by 3D echocardiography, Millar hemodynamics, and biopsies. The SERCA2a group had a well-maintained preload-recruitable stroke work at 3 months (decrease by 8±10% vs 42±12% with reporter gene controls; P<0.001). Left ventricular dP/dt followed the same pattern (no change vs 55% decrease; P<0.001). Left ventricular end-systolic volume was lower with SERCA2a (82.6±9.6 vs 99.4±9.7 mL; P=0.03); left ventricular end-diastolic volume, reflecting volume overload, was not significantly different (127.8±6.2 vs 134.3±9.4 mL). SERCA2a sheep showed a 15% rise in antiapoptotic pAkt versus a 30% reduction with the reporter gene (P<0.001). Prohypertrophic activated STAT3 was also 41% higher with SERCA2a than in controls (P<0.001). Proapoptotic activated caspase-3 rose >5-fold during 1 month in both SERCA2a and control animals (P=NS) and decreased by 19% at 3 months, remaining elevated in both groups.

CONCLUSIONS

In this controlled model, upregulating SERCA2a induced better function and lesser remodeling, with improved contractility, smaller volume, and activation of prohypertrophic/antiapoptotic pathways. Although caspase-3 remained activated in both groups, SERCA2a sheep had increased molecular antiremodeling "tone." We therefore conclude that upregulating SERCA2a inhibits MR-induced post-MI remodeling in this model and thus may constitute a useful approach to reduce the vicious circle of remodeling in ischemic MR.

Mitral leaflet adaptation to ventricular remodeling: prospective changes in a model of ischemic mitral regurgitation

BACKGROUND

Ischemic mitral regurgitation is caused by systolic traction on the mitral leaflets related to ventricular distortion. Little is known about how chronic tethering affects leaflet area, in part because it cannot be measured repeatedly in situ. Recently, a new method for 3D echocardiographic measurement of mitral leaflet area was developed and validated in vivo against sheep valves, later excised. Clinical studies (n=80) showed that mitral leaflet area increased by >30% in patients with inferior myocardial infarction and dilated cardiomyopathy versus normal; greater adaptation independently predicted less mitral regurgitation. This study explored whether mitral valve area changes over time within the same heart with ischemic mitral regurgitation.

METHODS AND RESULTS

Twelve sheep were studied at baseline and 3 months after inferior myocardial infarction by 3D echocardiography; 6 were untreated and 6 were treated initially with an epicardial patch to limit left ventricular dilation and mitral regurgitation. Untreated sheep developed left ventricular dilation at 3 months, with global dysfunction (mean+/-SD ejection fraction, 24+/-10% versus 44+/-10% with patching, P=0.02) and moderate mitral regurgitation (vena contracta, 5.0+/-1.0 versus 0.8+/-1.0 mm, P<0.0002). In untreated sheep, total diastolic leaflet area increased from 13.1+/-1.3 to 18.1+/-2.5 cm(2) (P=0.0001). In patched sheep, leaflet area at 3 months was not significantly different from baseline sheep values (13.0+/-1.1 versus baseline, 12.1+/-1.8 cm(2), P=0.31).

CONCLUSIONS

Mitral valve area, independent of systolic stretch, increases over time as the left ventricular remodels after inferior myocardial infarction. This increase, however, fails to compensate adequately for tethering to prevent mitral regurgitation. Understanding the mechanism of valve adaptation can potentially suggest new biological and surgical therapeutic targets.

A novel approach for reducing ischemic mitral regurgitation by injection of a polymer to reverse remodel and reposition displaced papillary muscles

BACKGROUND

Ischemic mitral regurgitation (MR) relates to displacement of the papillary muscles from ischemic ventricular distortion. We tested the hypothesis that repositioning of the papillary muscles can be achieved by injection of polyvinyl-alcohol (PVA) polymer, a biologically inert biomaterial that has been specially formulated to produce an encapsulated, stable, resilient gel once injected into the myocardium. The purpose is to materially support the infarcted myocardium while at the same time repositioning the papillary muscles that become apically tethered in MR.

METHODS AND RESULTS

Nine sheep underwent ligation of circumflex branches to produce acute ischemic MR. PVA polymer was then injected by echo guidance into the myocardium underlying the infarcted papillary muscle. Hemodynamic data, left ventricular ejection fraction, elastance, tau (relaxation constant), left ventricular stiffness coefficient, and 2-dimensional and 3-dimensional echocardiograms were obtained post-MR and post-PVA injection. One animal died after coronary ligation and 2 did not develop MR. In the remaining 6, moderate MR developed. With PVA injection, the MR decreased significantly from moderate to trace-mild (vena contracta: 5+/-0.4 mm versus 2+/-0.7 mm, post-MR versus post-PVA injection; P<0.0001). This was associated with a decrease in infarcted papillary muscle-to-mitral annulus tethering distance (27+/-4 to 24+/-4 mm, post-MR versus post-PVA, P<0.001). Importantly, PVA injection was not associated with significant decreases in left ventricular ejection fraction (43+/-6% versus 37+/-4%, post-MR versus post-PVA, P=nonsignificant), elastance (3.5+/-1.4 versus 2.9+/-1.3; post-MR versus post-PVA injection, P=nonsignificant). Measures of left ventricular diastolic function, tau (100+/-51 ms to 84+/-37 ms, post-MR versus post-PVA; P=nonsignificant), and left ventricular stiffness coefficient (0.18+/-0.12 versus 0.14+/-0.08, post-MR versus post-PVA; P=nonsignificant) did not increase post-PVA.

CONCLUSIONS

PVA polymer injection resulted in acute reverse remodeling of the ventricle with papillary muscle repositioning to decrease MR. This was not associated with an adverse effect on left ventricular systolic and diastolic function. This new approach to alter pathological anatomy after infarction may offer an alternative strategy for relieving ischemic MR by correcting the position of the affected papillary muscle, thus relieving apical tethering.

Management of coronary artery compression caused by recurrent aortic root abscess

Extrinsic coronary artery compression is a rare cause of coronary ischemia. We report the case of a 61-year-old male who developed a recurrent aortic root abscess causing extrinsic coronary artery compression. This complication occurred one year after undergoing aortic valve replacement and pericardial patch exclusion of an aortic root abscess. Surgical correction required debridement of the abscess and replacement of the aortic root with a homograft resulting in resolution of coronary compression.

Mitral leaflet adaptation to ventricular remodeling: occurrence and adequacy in patients with functional mitral regurgitation

BACKGROUND

Functional mitral regurgitation (MR) is caused by systolic traction on the mitral leaflets related to ventricular distortion. Little is known about whether chronic tethering causes the mitral leaflet area to adapt to the geometric needs imposed by tethering, in part because of inability to reconstruct leaflet area in vivo. Our aim was to explore whether adaptive increases in leaflet area occur in patients with functional MR compared with normal subjects and to test the hypothesis that leaflet area influences MR severity.

METHODS AND RESULTS

A new method for 3-dimensional echocardiographic measurement of mitral leaflet area was developed and validated in vivo against 15 sheep heart valves, later excised. This method was then applied in 80 consecutive patients from 3 groups: patients with normal hearts by echocardiography (n=20), patients with functional MR caused by isolated inferior wall-motion abnormality or dilated cardiomyopathy (n=29), and patients with inferior wall-motion abnormality or dilated cardiomyopathy but no MR (n=31). Leaflet area was increased by 35+/-20% in patients with LV dysfunction compared with normal subjects. The ratio of leaflet to annular area was 1.95+/-0.40 and was not different among groups, which indicates a surplus leaflet area that adapts to left-heart changes. In contrast, the ratio of total leaflet area to the area required to close the orifice in midsystole was decreased in patients with functional MR compared with those with normal hearts (1.29+/-0.15 versus 1.78+/-0.39, P=0.001) and compared with patients with inferior wall-motion abnormality or dilated cardiomyopathy but no MR (1.81+/-0.38, P=0.001). After adjustment for measures of LV remodeling and tethering, a leaflet-to-closure area ratio <1.7 was associated with significant MR (odds ratio 23.2, 95% confidence interval 2.0 to 49.1, P=0.02).

CONCLUSIONS

Mitral leaflet area increases in response to chronic tethering in patients with inferior wall-motion abnormality and dilated cardiomyopathy, but the development of significant MR is associated with insufficient leaflet area relative to that demanded by tethering geometry. The varying adequacy of leaflet adaptation may explain in part the heterogeneity of this disease among patients. The results suggest the need to understand the mechanisms that underlie leaflet adaptation and whether leaflet area can potentially be modified as part of the therapeutic approach.

Frequency and mechanism of persistent systolic anterior motion and mitral regurgitation after septal ablation in obstructive hypertrophic cardiomyopathy

Relief of obstruction using ventricular septal ablation (VSA) may not eliminate systolic anterior motion (SAM) of the mitral valve and mitral regurgitation (MR) in patients with obstructive hypertrophic cardiomyopathy. The hypothesis was that persistent SAM after VSA was secondary to anterior papillary muscle displacement and malcoaptation of mitral valve leaflets and that these findings could predict persistence of SAM. Echocardiograms were examined from 37 patients with obstructive hypertrophic cardiomyopathy before and 12+/-3 months after VSA. Anterior leaflet malposition (anterior-to-posterior leaflet coaptation position ratio), papillary muscle malposition (septal-to-lateral/left ventricular internal diameter ratio), and anterior position of coaptation relative to the septum (coaptation-to-septal distance) were assessed. MR proximal jet width was also measured. Of 37 patients, 30 underwent successful VSA (left ventricular outflow tract gradient reduction>50%); 22 of 30 and 7 of 7 with <50% reduction (total 29 of 37; 78%) showed persistent SAM at 12+/-3 months. These patients had more anterior malposition of the mitral valve and less MR reduction than those without SAM: anterior-to-posterior leaflet coaptation position ratio 0.42+/-0.06 versus 0.56+/-0.09, septal-to-lateral/left ventricular internal diameter ratio 0.39+/-0.12 versus 0.55+/-0.12, coaptation-to-septal distance 1.8+/-0.42 versus 2.8+/-0.30 cm, and MR reduction by 29+/-22% versus 71+/-12% (p<0.0001). Gradients, both at rest and provokable, were higher (27+/-33 vs 4+/-5 mm Hg, p=0.0004; >45 mm Hg in 9 vs 0, p=0.03, respectively) in patients with persistent SAM. Anterior malposition was present before VSA, with anterior-to-posterior leaflet coaptation position ratio<0.5 predicting SAM after VSA (p<0.0001). In conclusion, SAM and MR were often not eliminated using VSA. Mitral valve malposition was a strong predictor of SAM and MR reduction after VSA and may need to be considered in optimizing results of this procedure.

Early Repair of Moderate Ischemic Mitral Regurgitation Reverses Left Ventricular Remodeling: A Functional and Molecular Study

BACKGROUND

Mitral regurgitation (MR) doubles postmyocardial infarction (MI) mortality. We have shown that moderate MR augments remodeling in an apical MI model (no intrinsic MR) with independent left ventricle-to-left atrial MR-type flow. We hypothesized that repairing moderate MR 1 month after MI reverses this remodeling.

METHODS AND RESULTS

Anteroapical MIs were created in 18 sheep, and a left ventricle-to-left atrial shunt implanted in 12 (regurgitant fraction, 30%). Six sheep had the shunt closed at 1 month (repair group). Sheep were compared at baseline, and at 1 and 3 months. Sheep in the MI+MR (unrepaired) and repaired groups remodeled during the first month (120% increased left ventricular end-systolic volume [ESV; P<0.01]), but shunt closure reversed remodeling at 3 months, with end-diastolic volume (EDV) and ESV 135% and 128% of baseline versus 220% and 280% without repair (P<0.001). At 3 months, dP/dt and preload-recruitable stroke work were relatively maintained in the repaired and MI-only groups versus nearly 50% decreases without repair. Prohypertrophic gp130 and antiapoptotic pAkt increased followed by exhaustion below baseline without repair, but remained elevated at 3 months with repair or MI only. With repair, matrix metalloproteinase-2 decreased to < or = 50% that without repair in remote and border zones at 3 months, and the matrix metalloproteinase inhibitor TIMP-4 increased dramatically.

CONCLUSIONS

Early repair of moderate MR in the setting of apical MI substantially reverses the otherwise progressive remodeling process, with reduced left ventricular volumes, relatively maintained contractility, persistently activated intracellular signals promoting hypertrophy and opposing apoptosis, and reduced matrix proteolytic activity. These findings are of interest for the current controversy regarding potential benefits of repair of MR after MI.

Malignant tumours of the heart: a review of tumour type, diagnosis and therapy

Primary cardiac neoplasms are rare and occur less commonly than metastatic disease of the heart. In this overview, current published studies concerning malignant neoplasms of the heart are reviewed, together with some insights into their aetiology, diagnosis and management. We searched medline using the subject 'cardiac neoplasms'. We selected about 110 articles from between 1973 and 2006, of which 76 sources were used to complete the review. Sarcomas are the most common cardiac tumours and include myxosarcoma, liposarcoma, angiosarcoma, fibrosarcoma, leiomyosarcoma, osteosarcoma, synovial sarcoma, rhabdomyosarcoma, neurofibrosarcoma, malignant fibrous histiocytoma and undifferentiated sarcoma. The classic symptoms of cardiac tumours are intracardiac obstruction, signs of systemic embolisation, and systemic or constitutional symptoms. However, serious complications including stroke, myocardial infarction and even sudden death from arrhythmia may be the first signs of a tumour. Echocardiography and angiography are essential diagnostic tools for evaluating cardiac neoplasms. Computed tomography and magnetic resonance imaging studies have improved the diagnostic approach in recent decades. Successful treatment for benign cardiac tumours is usually achieved by surgical resection. Unfortunately, resection of the tumour is not always feasible. The prognosis after surgery is usually excellent in the case of benign tumours, but the prognosis of malignant tumours remains dismal. In conclusion, there are limited published data concerning cardiac neoplasms. Therefore, a high level of suspicion is required for early diagnosis. Surgery is the cornerstone of therapy. However, a multi-treatment approach, including chemotherapy, radiation as well as evolving approaches such as gene therapy, might provide a better palliative and curative result.

The Crossed Swords Sign: Insights into the Dilemma of Repair in Bileaflet Mitral Valve Prolapse

BACKGROUND

The need for bileaflet repair in bileaflet mitral valve prolapse (MVP) remains controversial. Will anterior leaflet prolapse resolve with posterior leaflet repair or should both leaflets be addressed? Single-leaflet MVP produces oppositely directed mitral regurgitant jets. Some patients show two crossed jets oppositely directed from the coaptation zone. We hypothesized that these indicate bileaflet lesions requiring complex repair.

METHODS

Echocardiograms and surgical reports of 52 consecutive patients with MVP undergoing surgery were reviewed.

RESULTS

First, all 14 patients with two oppositely directed jets had prolapse of more than one leaflet. Each jet was related to discrete leaflet distortions causing malcoaptation. Six underwent valve replacement. Seven had both leaflets repaired. One had posterior leaflet repair and annuloplasty, with persistent mitral regurgitation requiring valve replacement. Second, 36 of 38 patients with single jets had single-leaflet MVP. One underwent replacement; all others did well with single-leaflet repair. Two patients with bileaflet MVP but only one jet did well with single-leaflet repair or annuloplasty.

CONCLUSION

This crossed swords sign is an important clue to bileaflet mechanism of mitral regurgitation in MVP, associated with complex repair procedures. Thus, it provides a clue in the dilemma of bileaflet versus single-leaflet repair.

The Impact of Spontaneous Echocardiographic Contrast in Patients With Left Atrial Enlargement Undergoing Cardiac Valvular Surgery

OBJECTIVE

The aim of this study was to evaluate the impact of either left atrial or aortic spontaneous echocardiographic contrast (SEC), as identified on intraoperative transesophageal echocardiography, on short-term morbidity and mortality in patients with left atrial enlargement undergoing cardiac valvular surgery.

DESIGN

Retrospective and observational.

SETTING

Single-center, university teaching hospital.

PARTICIPANTS

The authors identified 197 patients (105 males and 92 females; mean age, 68 +/- 14 years) with left atrial enlargement who underwent surgical intervention for valvular heart disease from January 1, 2004 to January 1, 2005.

MAIN RESULTS

Of the total population, 40 patients (20.3%) showed left atrial SEC, and 10 patients (5.1%) showed aortic SEC. On multivariate analysis, increasing left atrial size and the absence of mitral regurgitation were independent predictors for the presence of left atrial SEC. On multivariate analysis, the presence of atrial fibrillation and a dilated descending aorta were predictive of aortic SEC. Although the identification of left atrial SEC was an echocardiographic marker of an increased risk for thromboembolic events postoperatively, this finding did not hold true for the presence of aortic SEC.

CONCLUSIONS

Intraoperative identification of left atrial dilatation or aortic dilatation is predictive of SEC in the left atrium or descending aorta, respectively. The identification of left atrial SEC is an echocardiographic marker of an increased risk for thromboembolic events in this high-risk population.