Outcomes and complications of nonagenarians undergoing cardiac surgery: a scoping review protocol.

INTRODUCTION: Continually rising life expectancy and a shift towards an ageing population are resulting in an increasing population of nonagenarians. By 2030, the global population of nonagenarians is expected to exceed 30 million. The incidence of symptomatic cardiac disease is reported to occur in 25% of those aged over 75 years. Therefore, the number of nonagenarians undergoing cardiac surgery is also expected to increase. A linear relationship between advanced age and surgical risk has previously been demonstrated; however, it is not yet known whether this knowledge extends to the perioperative course and mortality of nonagenarians undergoing cardiac surgery. This scoping review aims to review the literature, assess whether a deficiency exists in the published literature and potentially identify knowledge gaps to guide future efforts to improve the understanding of nonagenarians undergoing cardiac surgery. METHODS AND ANALYSIS: Following the relevant aspects of the Preferred Reporting Items for Systematic Review and Meta-Analysis Extension for Scoping Review guidelines, electronic databases of MEDLINE, EMBASE and the Cochrane Library will be systematically searched, with additional reference tracking of eligible studies. Studies reporting the outcomes of nonagenarians undergoing open cardiac surgery or minimally invasive cardiac surgery requiring cardiopulmonary bypass will be included. Screening and data extraction will be performed by two reviewers independently. The data will be analysed and summarised descriptively with a narrative approach. Qualitative data that capture quality-of-life outcomes will be subjected to thematic analysis where feasible. Additionally, reporting results will highlight similarities and differences in nonagenarian selection for surgery. ETHICS AND DISSEMINATION: Ethics approval was not required. The findings will be disseminated through professional networks, conference presentations and publications in scientific journals.

Modern Cardiac Surgical Outcomes in Nonagenarians: A Multicentre Retrospective Observational Study.

Background: There have been multiple recent advancements in the selection, optimisation and management of patients undergoing cardiac surgery. However, there is limited data regarding the outcomes in nonagenarians, despite this cohort being increasingly referred for these interventions. The objective of this study was to describe the patient characteristics, management and outcomes of a cohort of nonagenarians undergoing cardiac surgery receiving contemporary peri-operative care. Methods: After receiving ethics approval, we conducted a retrospective observational study of nonagenarians who had undergone cardiac surgery requiring a classic median sternotomy. All operative indications were included. We excluded patients who underwent transcatheter aortic valve implantation (TAVI), and surgery on the thoracic aorta via an endovascular approach (TEVAR). Patients undergoing TEVAR often have the procedure done under sedation and regional blocks with local anesthetic solution. There is no open incision and these patients do not require cardiopulmonary bypass. We also excluded patients undergoing minimally invasive mitral valve surgery via a videoscope assisted approach. These patients do not have a median sternotomy, have the procedure done via erector spinae block, and often are extubated on table. Data were collected from four hospitals in Victoria, Australia, over an 8-year period (January 2012-December 2019). The primary objective was to assess 6-month mortality in nonagenarian patients undergoing cardiac surgery and to provide a detailed overview of postoperative complications. We hypothesized that cardiac surgery in nonagenarian patients would be associated with a 6-month postoperative mortality <10%. As a secondary outcome, we hypothesized that significant postoperative complications (i.e., Clavien Dindo Grade IIIb or greater) would occur in > 30% of patients. Results: A total of 12,358 adult cardiac surgery patients underwent surgery during the study period, of whom 18 nonagenarians (0.15%) fulfilled inclusion criteria. The median (IQR) [min-max] age was 91.0 years (90.0:91.8) [90-94] and the median body mass index was 25.0 (kg/m2) (22.3:27.0). Comorbidities, polypharmacy, and frailty were common. The median predicted mortality as per EuroSCORE-II was 6.1% (4.1:14.5). There were no cases of intra-operative, in-hospital, or 6-month mortality. One (5.6%) patient experienced two Grade IIIa complications. Three (16.7%) patients experienced Grade IIIb complications. Three (16.7%) patients had an unplanned hospital readmission within 30 days of discharge. The median value for postoperative length of stay was 11.6 days (9.8:17.6). One patient was discharged home and all others were discharged to an inpatient rehabilitation facility. Conclusion: In this selected, contemporary cohort of nonagenarian patients undergoing cardiac surgery, postoperative 6-month mortality was zero. These findings support carefully selected nonagenarian patients being offered cardiac surgery (Trials Registry: https://www.anzctr.org.au/ACTRN12622000058774.aspx).

A spontaneous retroperitoneal haemorrhage resulting in abdominal compartment syndrome requiring laparotomy: A case report and proposed management algorithm.

INTRODUCTION AND IMPORTANCE: Spontaneous Retroperitoneal Haemorrhage (SRH) is a rare condition, which in its extreme state can result in Abdominal Compartment Syndrome (ACS). The aim of this case report is to provide an overview of the diagnosis and management of SRH and to present an algorithm to inform and guide clinical decision-making in the context of ACS. CASE PRESENTATION: A 74-year-old woman with multiple risk factors for SRH developed a tense abdomen in ICU post-cardiac graft study. Radiological imaging confirmed multiple bleeding points to the contralateral side of the graft access site. She underwent endovascular treatment for her condition, however, developed ACS necessitating surgical evacuation of the haematoma. CLINICAL DISCUSSION: SRH is a rare condition that may be difficult to diagnose on physical exam. Medical, endovascular and surgical approaches are recognised treatments. ACS is an extreme variant of SRH and although endovascular management can specifically address the acute bleed, surgical evacuation of the haematoma is the only treatment that can effectively reduce abdominal compartment pressures. CONCLUSION: SRH can cause abdominal compartment syndrome with subsequent multiorgan failure. Ultimately, as outlined in this case, surgical evacuation of the haematoma was the only treatment able to reduce abdominal compartment pressures.

Brainstem stroke caused by left atrial cardiac papillary fibroelastoma: an increasingly recognized rare cause of stroke.

Cardiac papillary fibroelastoma is a rare but increasingly recognized cause of embolic stroke that is prevalent in the older population and requires prompt surgical management. We report an unusual case of left atrial appendage cardiac fibroelastoma in a 76-year-old gentleman who presented with left internuclear ophthalmoplegia and ataxia, with corresponding diffusion-weighted imaging on magnetic resonance imaging of the brain. This case illustrates the importance of echocardiographic imaging in the workup of cardioembolic stroke in the older adult population in the acute setting.

Left Atrial Appendage Exclusion Using the AtriClip Device: A Case Series.

BACKGROUND: Atrial fibrillation (AF) affects 1.5-2% of the population and is associated with a five-fold increased lifetime risk of stroke [1]. The left atrial appendage (LAA) is the source of embolic strokes in up to 90% of patients with non-valvular AF with clots in the left atrium [2]. METHODS: We reviewed the clinical notes and echocardiographic findings of 20 patients who underwent open cardiac surgery in which concurrent AtriClip (Atricure Inc, Westchester, OH, USA) device insertion was attempted at our institution from July 2013 to February 2015. This was to examine the safety and efficacy of LAA exclusion with clip devices during open cardiac surgery. Indications for LAA exclusion included a history or suspicion of atrial arrhythmia, left ventricular dilatation, or a history of transient ischaemic attacks. RESULTS: All 20 of the 20 participants had successful placement of the clip device (100% success rate). There were no adverse events related to the device and no perioperative mortality. There were three late deaths due to chronic obstructive pulmonary disease (COPD), leukaemia, and refractory congestive cardiac failure. No late device related complications were found on follow-up imaging in the remaining patients. CONCLUSIONS: The results of our study demonstrate the LAA exclusion during open cardiac surgery with the AtriClip device is safe, has a 100% success rate, and appears to be stable over time.

Impact of the Cox-Maze IV Procedure on Left Atrial Mechanical Function.

BACKGROUND: The Cox-Maze IV procedure is a proven surgical treatment for atrial fibrillation (AF). Previous studies on the procedure and its effect on left atrial mechanical function have yielded mixed results. METHODS: Sixty-four (64) patients underwent Cox-Maze IV at St Vincent's Hospital, Melbourne between March 2010 and May 2016. Baseline characteristics were collected and outcomes assessed including rhythm analysis. Preoperative and postoperative transthoracic echocardiograms were reviewed. RESULTS: Fifty-seven (57) patients had complete follow-up with all clinical measures collected. The mean age was 71.1±10.2years, 63% being male. Fifty-eight per cent (58%) (33/57) of patients were in AF and 42% (24/57) in sinus rhythm (SR) at preoperative transthoracic echocardiography. Follow-up postoperative transthoracic echocardiography was performed at a mean of 2.3±1.9years. Nineteen (19) patients with a history of paroxysmal AF were in SR both preoperatively and postoperatively. In these patients, there was a significant decrease in Mitral A wave 0.63±0.28m/s (pre-op) vs 0.47±0.29m/s (post-op), p=0.044. There was a significant decrease in left ventricular ejection fraction (LVEF) postoperatively 64.2±9.7% vs 55.0±12.9%, p=0.005. At follow-up, 28% (16/57) were in AF, 61% (35/57) in SR, and 11% (6/57) in a paced rhythm. In a multivariate analysis, predictors of AF recurrence included higher LA volumes (p=0.042) and younger age at surgery p=0.030. Preoperative AF, sex and LVEF had no impact on AF recurrence. CONCLUSIONS: The Cox-Maze IV procedure, while effective in converting patients to sinus rhythm, may reduce left atrial mechanical function in patients with paroxysmal AF.

Sudden Cardiac Death in Patients With Ischemic Heart Failure Undergoing Coronary Artery Bypass Grafting: Results From the STICH Randomized Clinical Trial (Surgical Treatment for Ischemic Heart Failure).

BACKGROUND: The risk of sudden cardiac death (SCD) in patients with heart failure after coronary artery bypass graft surgery (CABG) has not been examined in a contemporary clinical trial of surgical revascularization. This analysis describes the incidence, timing, and clinical predictors of SCD after CABG. METHODS: Patients enrolled in the STICH trial (Surgical Treatment of Ischemic Heart Failure) who underwent CABG with or without surgical ventricular reconstruction were included. We excluded patients with prior implantable cardioverter-defibrillator and those randomized only to medical therapy. The primary outcome was SCD as adjudicated by a blinded committee. A Cox model was used to examine and identify predictors of SCD. The Fine and Gray method was used to estimate the incidence of SCD accounting for the competing risk of other deaths. RESULTS: Over a median follow-up of 46 months, 113 of 1411 patients who received CABG without (n = 934) or with (n = 477) surgical ventricular reconstruction had SCD; 311 died of other causes. The mean left ventricular ejection fraction at enrollment was 28±9%. The 5-year cumulative incidence of SCD was 8.5%. Patients who had SCD and those who did not die were younger and had fewer comorbid conditions than did those who died of causes other than SCD. In the first 30 days after CABG, SCD (n=5) accounted for 7% of all deaths. The numerically greatest monthly rate of SCD was in the 31- to 90-day time period. In a multivariable analysis including baseline demographics, risk factors, coronary anatomy, and left ventricular function, end-systolic volume index and B-type natriuretic peptide were most strongly associated with SCD. CONCLUSIONS: The monthly risk of SCD shortly after CABG among patients with a low left ventricular ejection fraction is highest between the first and third months, suggesting that risk stratification for SCD should occur early in the postoperative period, particularly in patients with increased preoperative end-systolic volume index or B-type natriuretic peptide. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT0002359.

Rapid-Deployment Versus Conventional Bio-Prosthetic Aortic Valve Replacement.

BACKGROUND: The use of rapid-deployment aortic valve replacement (RD-AVR) has burgeoned in recent years. There are few studies comparing RD-AVR to conventional aortic valve replacement (cAVR) and no studies where both were inserted via full sternotomy. As such, we reviewed our experience and compared the two approaches. METHODS: From 2008 to 2015, 597 patients underwent isolated aortic valve replacement ± coronary artery bypass grafting (CABG) at a single centre. During this period, 41 (7%) patients received RD-AVR and 556 (93%) received cAVR. Of those receiving RD-AVR, surgical access was via full median sternotomy in 40 (98%). Propensity score matching yielded 41 matched pairs. Perioperative outcomes were compared. RESULTS: After propensity score matching, the RD-AVR group had shorter aortic cross clamp (X-clamp) (RD-AVR: 71±33min vs. cAVR: 106±42min, p<0.01) and cardiopulmonary bypass (CPB) times (95±42min vs. 134±47min, p<0.01). There was no difference in 30-day mortality (RD-AVR: 2% vs. cAVR: 2%, p>0.99). RD-AVR patients required shorter mean ventilation (17±25 vs. 63±131hrs, p<0.01) and intensive care unit (ICU) stay (51±45 vs. 108±157hrs, p=0.03) times. RD-AVR also had reduced rates of new postoperative atrial arrhythmias (8% vs. 20%, p=0.02). Total length of postoperative hospital stay was similar. Haemodynamic performance for the RD-AVR was within acceptable limits. CONCLUSIONS: The use of RD-AVR results in shorter X-clamp and CPB times and is associated with reductions in perioperative morbidity. RD-AVR is becoming a valuable component of the surgeon's armamentarium in selected patients. Long-term follow-up will reveal the full potential of these devices.

Changes in the management of deep sternal wound infections: a 12-year review.

BACKGROUND: Deep sternal wound infection (DSWI) is a rare but life-threatening complication following cardiac surgery associated with increased morbidity and mortality. Management of these patients has evolved over the years and can include sternal rewiring, mediastinal irrigation, negative-pressure wound therapy (NPWT) dressing or repair with flaps. We reviewed changes in our management of DSWI and outcomes. METHODS: Using the Australian and New Zealand Society of Cardiac and Thoracic Surgeons database, 5472 underwent cardiac surgery at St Vincent's Hospital, Melbourne, and 42 were identified as developing DSWI requiring re-operation between June 2002 and September 2014. Data were collected pertaining to risk factors for DSWI, management strategies and outcomes. Patients were compared from a period prior to NPWT dressing use (June 2002-February 2006, n = 14) and since the NPWT has been used regularly in the management of DSWI (from March 2006, n = 28). Patients were also compared based on the requirement for flap closure of their sternal wound. RESULTS: Because of the widespread use of NPWT dressings, there is a trend towards fewer sternal infections requiring flap closure (25 versus 42.8%) and less post-operative complications after definitive closure (7.1 versus 28.6%). Before and after widespread NPWT use, patients require similar number of re-operations before closure and have no significant differences in time to definitive closure or length of hospital stay. CONCLUSION: The use of NPWT dressings as a bridge to definitive closure may reduce the need for more burdensome flap reconstruction, does not delay definitive reconstruction or prolong hospital stay and may reduce post-reconstruction complications requiring re-operation.

Calibrated integrated backscatter and myocardial fibrosis in patients undergoing cardiac surgery.

OBJECTIVE: The reported association between calibrated integrated backscatter (cIB) and myocardial fibrosis is based on study of patients with dilated or hypertrophic cardiomyopathy and extensive (mean 15-34%) fibrosis. Its association with lesser degrees of fibrosis is unknown. We examined the relationship between cIB and myocardial fibrosis in patients with coronary artery disease. METHODS: Myocardial histology was examined in left ventricular epicardial biopsies from 40 patients (29 men and 11 women) undergoing coronary artery bypass graft surgery, who had preoperative echocardiography with cIB measurement. RESULTS: Total fibrosis (picrosirius red staining) varied from 0.7% to 4%, and in contrast to previous reports, cIB showed weak inverse associations with total fibrosis (r=-0.32, p=0.047) and interstitial fibrosis (r=-0.34, p=0.03). However, cIB was not significantly associated with other histological parameters, including immunostaining for collagens I and III, the advanced glycation end product (AGE) N(ε)-(carboxymethyl)lysine (CML) and the receptor for AGEs (RAGE). When biomarkers were examined, cIB was weakly associated with log plasma levels of amino-terminal pro-B-type natriuretic peptide (r=0.34, p=0.03), creatinine (r=0.33, p=0.04) and glomerular filtration rate (r=-0.33, p=0.04), and was more strongly associated with log plasma levels of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) (r=0.44, p=0.01) and soluble RAGE (r=0.53, p=0.002). CONCLUSIONS: Higher cIB was not a marker of increased myocardial fibrosis in patients with coronary artery disease, but was associated with higher plasma levels of sVEGFR-1 and soluble RAGE. The role of cIB as a non-invasive index of fibrosis in clinical studies of patients without extensive fibrosis is, therefore, questionable.

Influence of Baseline Characteristics, Operative Conduct, and Postoperative Course on 30-Day Outcomes of Coronary Artery Bypass Grafting Among Patients With Left Ventricular Dysfunction: Results From the Surgical Treatment for Ischemic Heart Failure (STICH) Trial.

BACKGROUND: Patients with severe left ventricular dysfunction, ischemic heart failure, and coronary artery disease suitable for coronary artery bypass grafting (CABG) are at higher risk for surgical morbidity and mortality. Paradoxically, those patients with the most severe coronary artery disease and ventricular dysfunction who derive the greatest clinical benefit from CABG are also at the greatest operative risk, which makes decision making regarding whether to proceed to surgery difficult in such patients. To better inform such decision making, we analyzed the Surgical Treatment for Ischemic Heart Failure (STICH) CABG population for detailed information on perioperative risk and outcomes. METHODS AND RESULTS: In both STICH trials (hypotheses), 2136 patients with a left ventricular ejection fraction of ≤35% and coronary artery disease were allocated to medical therapy, CABG plus medical therapy, or CABG with surgical ventricular reconstruction. Relationships of baseline characteristics and operative conduct with morbidity and mortality at 30 days were evaluated. There were a total of 1460 patients randomized to and receiving surgery, and 346 (≈25%) of these high-risk patients developed a severe complication within 30 days. Worsening renal insufficiency, cardiac arrest with cardiopulmonary resuscitation, and ventricular arrhythmias were the most frequent complications and those most commonly associated with death. Mortality at 30 days was 5.1% and was generally preceded by a serious complication (65 of 74 deaths). Left ventricular size, renal dysfunction, advanced age, and atrial fibrillation/flutter were significant preoperative predictors of mortality within 30 days. Cardiopulmonary bypass time was the only independent surgical variable predictive of 30-day mortality. CONCLUSIONS: CABG can be performed with relatively low 30-day mortality in patients with left ventricular dysfunction. Serious postoperative complications occurred in nearly 1 in 4 patients and were associated with mortality. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00023595.

Comparison of Transesophageal and Transthoracic Echocardiographic Measurements of Mechanism and Severity of Mitral Regurgitation in Ischemic Cardiomyopathy (from the Surgical Treatment of Ischemic Heart Failure Trial).

Mitral regurgitation (MR) is common in ischemic heart disease and contributes to symptoms and mortality. This report compares the results of baseline transesophageal echocardiography (TEE) and transthoracic echocardiography (TTE) imaging of the mechanism and severity of functional MR in patients with ischemic cardiomyopathy in the Surgical Treatment for Ischemic Heart Failure (STICH) trial. Independent core laboratories measured both TTE and TEE images on 196 STICH participants. Common measurements to both models included MR grade, mitral valve tenting height and tenting area, and mitral annular diameter. For each parameter, correlations were assessed using Spearman rank correlation coefficients. A modest correlation was present between TEE and TTE for overall MR grade (n = 176, r = 0.52). For mechanism of MR, modest correlations were present for long-axis tenting height (n = 152, r = 0.35), tenting area (n = 128, r = 0.27), and long-axis mitral annulus diameter (n = 123, r = 0.41). For each measurement, there was significant scatter. Potential explanations for the scatter include different orientation of the imaging planes between TEE and TTE, a mean temporal delay of 6 days between TEE and TTE, and statistically significant differences in heart rate and blood pressure and weight between studies. In conclusion, TEE and TTE measurements of MR mechanism and severity correlate only modestly with enough scatter in the data that they are not interchangeable.

Predicting adverse outcomes in elective coronary artery bypass graft surgery using pre-operative troponin I levels.

BACKGROUND: Cardiac troponins are frequently measured as part of the pre-operative work-up of patients prior to coronary artery bypass graft surgery (CABG). The utility of measuring these levels in elective patients, and the clinical implication of an abnormal result are unclear. The following study investigates the relationship between cardiac troponin I (cTnI) measured as part of a routine pre-operative work-up and outcomes following CABG. METHODS: From January 2010 to December 2012, 378 patients underwent isolated, elective CABG and had cTnI measured prospectively, as part of their pre-operative work-up. Patients were divided into normal (Group I) and elevated (Group II) cTnI groups. Pre-operative, operative and post-operative data were obtained from our institution's prospectively collected database. RESULTS: Elevated cTnI was present in 47 patients (12.4%) pre-operatively. Intra-operative variables did not differ between the elevated cTnI and control groups. Both 30-day mortality (Group I: 0.9% v Group II: 6.4%, p=0.03) and cardiac arrest (Group I: 1.5% v Group II: 8.5%, p=0.01) were significantly more frequent in the elevated cTnI group. In multivariable analysis, elevated cTnI remained a predictor for cardiac arrest (OR 5.8, 95% CI 1.2 - 29.2). CONCLUSIONS: Patients presenting for elective CABG frequently have elevated cTnI on pre-operative work-up. These patients may be at a greater risk of 30-day mortality and cardiac arrest. Routine pre-operative measurement of cTnI may alert clinicians to a higher operative risk.

Prophylactic epicardial left ventricular lead implantation for biventricular pacing during operations.

BACKGROUND: Surgical epicardial left ventricular (LV) lead implantation for biventricular pacing has advantages over the transvenous approach in cardiac surgical patients. We investigated the benefit of concomitant prophylactic LV lead implantation during open heart operations and subsequent lead performance after patients with impaired LV function receive a biventricular device. METHODS: Retrospective data of 4,844 patients undergoing cardiac operations through a sternotomy between January 2001 and December 2011 were analyzed. Of these, 380 patients (7.8%) had severe impairment of LV function (contrast left ventriculogram showing grade 4 estimated ejection fraction or echocardiogram showing LV ejection fraction<0.30). LV lead implantation was performed in patients in whom recovery of LV function was unlikely. Lead performance data were collected at follow-up. RESULTS: LV lead implantation occurred in 95 patients (25%), and 29 (30.5%) subsequently received a biventricular device. Of patients with impaired LV function, more patients with prophylactic LV leads underwent biventricular implant than those without LV leads (30.5% vs 1.1%, p<0.0001). The median interval from LV lead implantation to connection to a biventricular device was 30 days (interquartile range, 5.5 to 145 days). At a median follow-up of 437.5 days (interquartile range, 13.8 to 1198 days), the mean pacing threshold (1.25±0.46 vs 1.58±0.66 volts, p=0.069) and impedance (383.81±70.33 vs 448.6±200.1 Ohms, p=0.168) remained stable compared with time of biventricular device connection. CONCLUSIONS: A significant proportion of patients with poor LV function undergoing cardiac operations may benefit from concomitant LV lead implantation. Subsequent lead performance appears satisfactory. Epicardial LV lead placement is easily accomplished during open heart operations and should be considered before the operation.

The 'down-under repair' for ischaemic mitral regurgitation.

Current surgical management of restrictive ischaemic mitral regurgitation (IMR) includes mitral valve annuloplasty (MVA) using an undersized ring when the mechanism is secondary to leaflet restriction. In our experience, MVA alone is inadequate to eliminate mitral incompetence in these patients. We report the 'Down-Under Repair' as an adjunctive concept for the treatment of a subset of patients with restrictive IMR and associated inferobasal left ventricular aneurysm. The 'Down-Under Repair' reduces mitral leaflet restriction by approximating the origin of the posterior papillary muscle towards the mitral annulus. Midterm results demonstrated sustained valvular competence and symptomatic improvement.

Obesity is associated with lower coronary microvascular density.

BACKGROUND: Obesity is associated with diastolic dysfunction, lower maximal myocardial blood flow, impaired myocardial metabolism and increased risk of heart failure. We examined the association between obesity, left ventricular filling pressure and myocardial structure. METHODS: We performed histological analysis of non-ischemic myocardium from 57 patients (46 men and 11 women) undergoing coronary artery bypass graft surgery who did not have previous cardiac surgery, myocardial infarction, heart failure, atrial fibrillation or loop diuretic therapy. RESULTS: Non-obese (body mass index, BMI, ≤ 30 kg/m(2), n=33) and obese patients (BMI >30 kg/m(2), n=24) did not differ with respect to myocardial total, interstitial or perivascular fibrosis, arteriolar dimensions, or cardiomyocyte width. Obese patients had lower capillary length density (1145 ± 239, mean ± SD, vs. 1371 ± 333 mm/mm(3), P=0.007) and higher diffusion radius (16.9 ± 1.5 vs. 15.6 ± 2.0 µm, P=0.012), in comparison with non-obese patients. However, the diffusion radius/cardiomyocyte width ratio of obese patients (0.73 ± 0.11 µm/µm) was not significantly different from that of non-obese patients (0.71 ± 0.11 µm/µm), suggesting that differences in cardiomyocyte width explained in part the differences in capillary length density and diffusion radius between non-obese and obese patients. Increased BMI was associated with increased pulmonary capillary wedge pressure (PCWP, P<0.0001), and lower capillary length density was associated with both increased BMI (P=0.043) and increased PCWP (P=0.016). CONCLUSIONS: Obesity and its accompanying increase in left ventricular filling pressure were associated with lower coronary microvascular density, which may contribute to the lower maximal myocardial blood flow, impaired myocardial metabolism, diastolic dysfunction and higher risk of heart failure in obese individuals.

Mechanisms of functional mitral regurgitation in ischemic cardiomyopathy determined by transesophageal echocardiography (from the Surgical Treatment for Ischemic Heart Failure Trial).

The mechanisms underlying functional mitral regurgitation (MR) and the relation between mechanism and severity of MR have not been evaluated in a large, multicenter, randomized controlled trial. Transesophageal echocardiography (TEE) was performed in 215 patients at 17 centers in the Surgical Treatment for Ischemic Heart Failure (STICH) trial. Both 2-dimensional (n = 215) and 3-dimensional (n = 81) TEEs were used to assess multiple quantitative measurements of the mechanism and severity of MR. By 2-dimensional TEE, leaflet tenting area, anterior and posterior leaflet angles, mitral annulus diameter, left ventricular (LV) end-systolic volume index, LV ejection fraction (LVEF), and sphericity index (p <0.05 for all) were significantly different across MR grades. By 3-dimensional TEE, mitral annulus area, leaflet tenting area, LV end-systolic volume index, LVEF, and sphericity index (p <0.05 for all) were significantly different across MR grades. A multivariate analysis showed a trend for annulus area (p = 0.069) and LV end-systolic volume index (p = 0.071) to predict effective regurgitant orifice area and for annulus area (p = 0.018) and LV end-systolic volume index (p = 0.073) to predict vena contracta area. In the STICH trial, multiple quantitative parameters of the mechanism of functional MR are related to MR severity. The mechanism of functional MR in ischemic cardiomyopathy is heterogeneous, but no single variable stands out as a strong predictor of quantitative severity of MR.