Three-Dimensional Echocardiographic Assessment of Mitral Annular Physiology in Patients With Degenerative Mitral Valve Regurgitation Undergoing Surgical Repair: Comparison between Early- and Late-Stage Severe Mitral Regurgitation.

BACKGROUND: Ventricular-annular decoupling is thought to exist in all degenerative myxomatous mitral valve (MV) diseases. However, the annular physiology of degenerative MV disease may differ when severe mitral regurgitation (MR) presents at different stages. The aim of this study was to assess differences in mitral annular physiology and surgical effects between early- and late-stage severe MR. METHODS: Three-dimensional (3D) transesophageal echocardiography was performed before and after MV surgery in 74 patients with degenerative MV disease, including 57 with early-stage severe MR (without left ventricular remodeling) and 17 with late-stage MR (with left ventricular remodeling). A control group comprised 46 patients without MV disease. Novel 3D MV software was used to evaluate mitral annular dynamics. The degree of annular saddle shape was calculated as the ratio of annular height (AH) to lateromedial diameter (LM). Ventricular-annular decoupling was defined as insufficient systolic AH/LM compared with the control group. RESULTS: Prebypass 3D measurements demonstrated that systolic AH/LM in the early-stage group (0.19 ± 0.04) was similar to that in the control group (0.21 ± 0.05; P = .101), while systolic AH/LM in the late-stage group (0.17 ± 0.04) was lower than that in the control group (P = .011). Postbypass comparison showed saddle shape accentuation in the early-stage group (0.20 ± 0.04), similar to that in the control group (P = .3127); the mitral annulus remained flat in the late-stage group (0.17 ± 0.03; P = .004). CONCLUSIONS: Ventricular-annular decoupling, present in the late-stage group, was absent in the early-stage group. MV repair surgery did not disrupt mitral annular saddle shape in the early-stage group; however, it failed to correct annular dysfunction in the late-stage group. Sequential 3D transesophageal echocardiographic analysis provides comprehensive mitral annular evaluation beyond conventional two-dimensional parameters for determining stages of severe MR.

Cardiovascular Outcomes Assessment of the MitraClip in Patients with Heart Failure and Secondary Mitral Regurgitation: Design and rationale of the COAPT trial.

BACKGROUND: Patients with heart failure (HF) and symptomatic secondary mitral regurgitation (SMR) have a poor prognosis, with morbidity and mortality directly correlated with MR severity. Correction of isolated SMR with surgery is not well established in this population, and medical management remains the preferred approach in most patients. The Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation (COAPT) trial was designed to determine whether transcatheter mitral valve (MV) repair with the MitraClip device is safe and effective in patients with symptomatic HF and clinically significant SMR. STUDY DESIGN: The COAPT trial is a prospective, randomized, parallel-controlled, open-label multicenter study of the MitraClip device for the treatment of moderate-to-severe (3+) or severe (4+) SMR (as verified by an independent echocardiographic core laboratory) in patients with New York Heart Association class II-IVa HF despite treatment with maximally tolerated guideline-directed medical therapy (GDMT) who have been determined by the site's local heart team as not appropriate for MV surgery. A total of 614 eligible subjects were randomized in a 1:1 ratio to MV repair with the MitraClip plus GDMT versus GDMT alone. The primary effectiveness end point is recurrent HF hospitalizations through 24 months, analyzed when the last subject completes 12-month follow-up, powered to demonstrate superiority of MitraClip therapy. The primary safety end point is a composite of device-related complications at 12 months compared to a performance goal. Follow-up is ongoing, and the principal results are expected in late 2018. CONCLUSIONS: HF patients with clinically significant SMR who continue to be symptomatic despite optimal GDMT have limited treatment options and a poor prognosis. The randomized COAPT trial was designed to determine the safety and effectiveness of transcatheter MV repair with the MitraClip in symptomatic HF patients with moderate-to-severe or severe SMR.

Evaluation of The Society of Thoracic Surgeons Online Risk Calculator for Assessment of Risk in Patients Presenting for Aortic Valve Replacement After Prior Coronary Artery Bypass Graft: An Analysis Using the STS Adult Cardiac Surgery Database.

BACKGROUND: Accurate risk assessment in patients presenting for aortic valve replacement (AVR) after prior coronary artery bypass grafting (CABG) is essential for appropriate selection of surgical versus percutaneous therapy. METHODS: We included 6,534 patients in The Society for Thoracic Surgeons (STS) Adult Cardiac Surgery Database (October 2009 through December 2013) who underwent elective, isolated reoperative AVR for aortic stenosis after prior CABG. Case-specific PROM was calculated and observed-to-expected ratios were inspected across the spectrum of risk. A cohort-specific recalibration equation was derived using logistic regression: = expit(-0.6453+0.6147*logit(PROM) -0.0709*logit(PROM)(ˆ)2), where PROM is the predicted risk of mortality. The proportion of patients reclassified as low (PROM < 4%), intermediate (4% to < 8%), high (8% to < 12%), and very high risk (≥ 12%) was calculated using the recalibration equation. The performance of the cohort-specific recalibration equation was then compared with the generic recalibration for quarterly STS reports. RESULTS: The STS online risk calculator overestimates risk for low, intermediate, and high risk categories. Using the recalibrated risk equation, a substantial proportion of patients were reclassified as the following: 25.5% from intermediate to low risk; 39.7% from high to intermediate risk; and 41.5% from very high to high risk. Comparison of the cohort-specific recalibration equation to the generic quarterly STS recalibration demonstrated very similar results. CONCLUSIONS: In patients presenting for AVR after prior CABG, the STS online risk calculator overestimates risk for all but the highest risk patients. Using a cohort-specific recalibration equation, a substantial proportion of patients would be downgraded to lower risk categories. The cohort-specific recalibration correlates well with the existing generic quarterly STS recalibration. The findings of this study support recommendations for periodic recalibration of the online risk calculator in order to facilitate clinical decision making in real time.

Appropriate patient selection or health care rationing? Lessons from surgical aortic valve replacement in the Placement of Aortic Transcatheter Valves I trial.

OBJECTIVES: The study objectives were to (1) compare the safety of high-risk surgical aortic valve replacement in the Placement of Aortic Transcatheter Valves (PARTNER) I trial with Society of Thoracic Surgeons national benchmarks; (2) reference intermediate-term survival to that of the US population; and (3) identify subsets of patients for whom aortic valve replacement may be futile, with no survival benefit compared with therapy without aortic valve replacement. METHODS: From May 2007 to October 2009, 699 patients with high surgical risk, aged 84 ± 6.3 years, were randomized in PARTNER-IA; 313 patients underwent surgical aortic valve replacement. Median follow-up was 2.8 years. Survival for therapy without aortic valve replacement used 181 PARTNER-IB patients. RESULTS: Operative mortality was 10.5% (expected 9.3%), stroke 2.6% (expected 3.5%), renal failure 5.8% (expected 12%), sternal wound infection 0.64% (expected 0.33%), and prolonged length of stay 26% (expected 18%). However, calibration of observed events in this relatively small sample was poor. Survival at 1, 2, 3, and 4 years was 75%, 68%, 57%, and 44%, respectively, lower than 90%, 81%, 73%, and 65%, respectively, in the US population, but higher than 53%, 32%, 21%, and 14%, respectively, in patients without aortic valve replacement. Risk factors for death included smaller body mass index, lower albumin, history of cancer, and prosthesis-patient mismatch. Within this high-risk aortic valve replacement group, only the 8% of patients with the poorest risk profiles had estimated 1-year survival less than that of similar patients treated without aortic valve replacement. CONCLUSIONS: PARTNER selection criteria for surgical aortic valve replacement, with a few caveats, may be more appropriate, realistic indications for surgery than those of the past, reflecting contemporary surgical management of severe aortic stenosis in high-risk patients at experienced sites.

Minimally invasive mitral valve surgery: Does it make a difference?

Minimally invasive mitral valve surgery (MIMVS) has emerged as an alternative approach to conventional sternotomy to perform mitral valve repair and replacement with equivalent results. This strategy was developed to decrease surgical trauma by minimizing the size of incisions and permits excellent exposure of the mitral valve thereby avoiding conventional full sternotomy. The purpose of this review is to provide a critical, objective, balanced, and evidence-based analysis of the literature to understand advantages, potential scope, and the utility of these minimally invasive approaches to the mitral valve in modern cardiac care.

Costs of periprocedural complications in patients treated with transcatheter aortic valve replacement: results from the Placement of Aortic Transcatheter Valve trial.

BACKGROUND: In patients with severe aortic stenosis, transcatheter aortic valve replacement (TAVR) improves survival when compared with nonsurgical therapy but with higher in-hospital and lifetime costs. Complications associated with TAVR may decrease with greater experience and improved devices, thereby reducing the overall cost of the procedure. Therefore, we sought to estimate the effect of periprocedural complications on in-hospital costs and length of stay of TAVR. METHODS AND RESULTS: Using detailed cost data from 406 TAVR patients enrolled in the Placement of Aortic Transcatheter Valve (PARTNER) I trial, we developed multivariable models to estimate the incremental cost and length of stay associated with specific periprocedural complications. Attributable costs and length of stay for each complication were calculated by multiplying the independent cost of each event by its frequency in the treatment group. Mean cost for the initial hospitalization was $79 619±40 570 ($50 891 excluding the valve); 49% of patients had ≥1 complication. Seven complications were independently associated with increased hospital costs, with major bleeding, arrhythmia, and death accounting for the largest attributable cost per patient. Renal failure and the need for repeat TAVR, although less frequent, were also associated with substantial incremental and attributable costs. Overall, complications accounted for $12 475 per patient in initial hospital costs and 2.4 days of hospitalization. CONCLUSIONS: In the PARTNER trial, periprocedural complications were frequent, costly, and accounted for ≈25% of non-implant-related hospital costs. Avoidance of complications should improve the cost-effectiveness of TAVR for inoperable and high-risk patients, but reductions in the cost of uncomplicated TAVR will also be necessary for optimal efficiency. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00530894.

Risk assessment methods for cardiac surgery and intervention.

Surgical risk models estimate operative outcomes while controlling for heterogeneity in 'case mix' within and between institutions. In cardiac surgery, risk models are used for patient counselling, surgical decision-making, clinical research, quality assurance and improvement, and financial reimbursement. Importantly, risk models are only as good as the databases from which they are derived; physicians and investigators should, therefore, be aware of shortcomings of clinical and administrative databases used for modelling risk estimates. The most frequently modelled outcome in cardiac surgery is 30-day mortality. However, results of randomized trials to compare conventional surgery versus transcatheter aortic valve implantation (TAVI) indicate attrition of surgical patients at 2-4 months postoperatively, suggesting that 3-month survival or mortality might be an appropriate procedural end point worth modelling. Risk models are increasingly used to identify patients who might be better-suited for TAVI. However, the appropriateness of available statistical models in this application is controversial, particularly given the tendency of risk models to misestimate operative mortality in high-risk patient subsets. Incorporation of new risk factors (such as previous mediastinal radiation, liver failure, and frailty) in future surgical or interventional risk-prediction tools might enhance model performance, and thereby optimize patient selection for TAVI.

Hypothermia and operative mortality during on-pump coronary artery bypass grafting.

OBJECTIVE: Controversy surrounds the effect of hypothermia on operative mortality during cardiac surgery. The present study accessed a large clinical database of coronary artery bypass graft operations to address the issue. METHODS: A retrospective review of the Society of Thoracic Surgeons Adult Cardiac Surgery Database identified patients treated with isolated, nonemergency, on-pump coronary artery bypass grafting from July 2011 to December 2012. The patients were divided into 3 groups according to their lowest core temperature during the procedure: moderate hypothermia (≤ 34 °C), mild hypothermia (>34 °C but ≤ 36 °C), and normothermia (>36 °C). The primary endpoint of the study was operative mortality, defined according to the Database criteria. RESULTS: During the study period, 142,541 patients were available for analysis; 94,777 (66.5%) received moderate hypothermia, 42,750 (30.3%) mild hypothermia, and 5014 (3.5%) normothermia. Operative mortality occurred in 1394 patients (1.5%) in the moderate hypothermia, 534 (1.3%) in the mild hypothermia, and 105 (2.1%) in the normothermia group. Multivariate analysis identified hypothermia (both mild [odds ratio, 0.66; 95% confidence interval, 0.54-0.81; P < .0001] and moderate [odds ratio, 0.73; 95% confidence interval, 0.60-0.89; P = .0015]) was protective against operative mortality compared with normothermia. No incremental benefit was noted between the different hypothermia grades (P = .0827). CONCLUSIONS: Most patients receive hypothermia during on-pump coronary artery bypass grafting. Hypothermia is protective against operative mortality compared with normothermia in such patients. Moderate hypothermia does not provide additional survival benefit.

Improving affordability through innovation in the surgical treatment of mitral valve disease.

OBJECTIVE: To determine whether technically innovative cardiac surgical platforms (ie, robotics) deployed in conjunction with surgical process improvement (systems innovation) influence total hospital costs to address the concern that expanding adoption might increase health care expenses. PATIENTS AND METHODS: We studied 185 propensity-matched patient pairs (370 patients) undergoing isolated conventional open vs robotic mitral valve repair with identical repair techniques and care teams between July 1, 2007, and January 31, 2011. Two time periods were considered, before the implementation of system innovations (pre-July 2009) and after implementation. Generalized linear mixed models were used to estimate the effect of the type of surgery on cost while adjusting for a time effect. RESULTS: Baseline characteristics of the study patients were similar, and all patients underwent successful mitral valve repair with no early deaths. Median length of stay (LOS) for patients undergoing open repair was unchanged at 5.3 days (P=.636) before and after systems innovation implementation, and was lower for robotic patients at 3.5 and 3.4 days, respectively (P=.003), throughout the study. The overall median costs associated with open and robotic repair were $31,838 and $32,144, respectively (P=.32). During the preimplementation period, the total cost was higher for robotic ($34,920) than for open ($32,650) repair (P<.001), but during the postimplementation period, the median cost of robotic repair ($30,606) became similar to that of open repair ($31,310) (P=.876). The largest decrease in robotic cost was associated with more rapid ventilator weaning and shortened median intensive care unit LOS, from 22.7 hours before July 2009 to 9.3 hours after implementation of systems innovations (P<.001). CONCLUSION: Following the introduction of systems innovation, the total hospital cost associated with robotic mitral valve repair has become similar to that for a conventional open approach, while facilitating quicker patient recovery and diminished utilization of in-hospital resources. These data suggest that innovations in techniques (robotics) along with care systems (process improvement) can be cost-neutral, thereby improving the affordability of new technologies capable of improving early patient outcomes.

Assessment of coronary artery disease risk in 5463 patients undergoing cardiac surgery: when is preoperative coronary angiography necessary?

OBJECTIVES: We sought to critically analyze the routine use of conventional coronary angiography (CCA) before noncoronary cardiac surgery and to assess clinical prediction models that might allow more selective use of CCA in this setting. METHODS: We studied 5463 patients undergoing aortic valve surgery, mitral valve surgery, or septal myectomy with or without coronary artery bypass grafting from 2001 to 2010. Preoperative CCAs were evaluated for the presence of significant coronary artery disease (CAD). Random forests and logistic regression methods were used to determine the predictors of significant (≥50%) coronary stenosis. RESULTS: Preoperative CCA was performed in 4711 patients (86%). Two thirds of those with angina, previous myocardial infarction, or percutaneous coronary intervention had significant CAD found on CCA, versus one third of patients free of these risk factors (P < .001). Among 3019 patients without angina, previous myocardial infarction or percutaneous coronary intervention, older age, male gender, diabetes, and peripheral vascular disease independently predicted significant CAD (P < .001 for all; C-index = 0.74). Specifically, a multivariate model with these variables identified 10% (301 of 3019) of patients as having a low (≤10%) probability of coronary stenosis, of whom fewer than 5% had significant CAD and fewer than 1% had left main or triple-vessel coronary disease. CONCLUSIONS: In the absence of angina, previous myocardial infarction, or percutaneous coronary intervention, preoperative CCA identified significant CAD in only one third of patients. Our clinical prediction models could enhance the identification of patients at low risk of significant CAD for whom CCA might potentially be avoided before cardiac surgery. This strategy may improve the efficiency of cardiac surgical care delivery by diminishing procedure-related morbidity and offering significant cost savings.

Comprehensive hemodynamic assessment of 368 normal St. Jude Medical mechanical mitral valve prostheses based on early postimplantation echocardiographic studies.

BACKGROUND: Two-dimensional and Doppler-derived echocardiographic data on normal St. Jude Medical mechanical mitral valve prosthesis function have been reported but remain limited. METHODS: Comprehensive retrospective two-dimensional and Doppler echocardiographic assessment of 368 normal St. Jude Medical mechanical mitral valve prostheses was performed early after implantation. The early postimplantation hemodynamic profiles of 98 patients were compared with profiles obtained by follow-up transthoracic echocardiography performed <13 months after implantation. RESULTS: Using mean ± 2 SDs to define the normal distribution of values for Doppler-derived hemodynamic variables, the calculated normal ranges of values were as follows: mean gradient, 2 to 7 mm Hg; peak early mitral diastolic velocity (E velocity), 1.1 to 2.4 m/sec; time-velocity integral of the mitral valve prosthesis (TVIMVP) 20 to 50 cm; ratio of the TVIMVP to the time-velocity integral of the left ventricular outflow tract (TVILVOT), 0.9 to 2.5; pressure half-time, 35 to 99 msec; and effective orifice area, 1.12 to 3.24 cm(2). Patients with severe prosthesis-patient mismatch (ie, indexed effective orifice area ≤ 0.9 cm(2)/m(2)) had significantly higher mean gradients, E velocity, TVIMVP, and TVIMVP/TVILVOT. There was a trend for longer pressure half-times for patients with severe prosthesis-patient mismatch than for patients without severe prosthesis-patient mismatch, but none of these patients had pressure half-times > 130 msec. Among the 98 patients with follow-up transthoracic echocardiography <1 year after implantation, no significant differences were observed between early postimplantation findings and follow-up hemodynamic profiles. CONCLUSIONS: This study establishes parameters (mean ± 2 SDs) defining the distribution of values for Doppler-derived hemodynamic data with normal St. Jude Medical mechanical mitral valve prostheses. Prostheses with hemodynamic values outside these parameters are likely dysfunctional; however, prosthesis dysfunction may be present even when hemodynamic values are within these ranges.

Management of mild aortic stenosis at the time of coronary artery bypass surgery: should the valve be replaced?

BACKGROUND: General consensus favors aortic valve replacement (AVR) for patients with moderate aortic stenosis (AS) undergoing coronary artery bypass graft surgery (CABG); however, the management of similar patients with mild AS is controversial. We therefore investigated such patients to determine incremental risk of concomitant AVR, progression of AS among those undergoing CABG alone, and operative risk of AVR after prior CABG. METHODS: Between January 1993 and December 2003, 316 consecutive patients with mild AS (mean gradient >15, <30 mm Hg) underwent CABG only (107) or CABG plus AVR (209). Follow-up was obtained by review of the medical record, the Social Security Death Index, and postal questionnaire. RESULTS: The operative mortality was 3.7% for CABG only and 4.3% for CABG plus AVR (p = 1). Survival at a mean of 5.4 +/- 3.6 years was similar. Multivariate predictors of late mortality included comorbid illnesses (Charlson comorbidity score and age-weighted summary of diseases; p = 0.001), small body surface area (p = 0.001), low ejection fraction (p = 0.007), preoperative permanent pacemaker (p = 0.04), and congestive heart failure (p = 0.046), but not AVR. Twenty-three CABG-only patients (21%) underwent subsequent AVR (mean 5.6 +/- 1.8 years) without mortality. Aortic valve replacement at the time of initial CABG (p <0.001) and older age (p = 0.02) were multivariate predictors of freedom from reoperation. CONCLUSIONS: Prophylactic AVR for mild AS at CABG does not confer a survival benefit, and the likelihood of requiring AVR after CABG alone is low in the first 5 years. The decision to intervene on the valve is critically dependent upon the incremental operative risk imposed by concomitant AVR and late survival.

Real-time three-dimensional transesophageal echocardiography in the intraoperative assessment of mitral valve disease.

BACKGROUND: The aims of this study were to evaluate the feasibility of real-time 3-dimensional (3D) transesophageal echocardiography in the intraoperative assessment of mitral valve (MV) pathology and to compare this novel technique with 2-dimensional (2D) transesophageal echocardiography. METHODS: Forty-two consecutive patients undergoing MV repair for mitral regurgitation (MR) were studied prospectively. Intraoperative 2D and 3D transesophageal echocardiographic (TEE) examinations were performed using a recently introduced TEE probe that provides real-time 3D imaging. Expert echocardiographers blinded to 2D TEE findings assessed the etiology of MR on 3D transesophageal echocardiography. Similarly, experts blinded to 3D TEE findings assessed 2D TEE findings. Both were compared with the anatomic findings reported by the surgeon. RESULTS: At the time of surgical inspection, ischemic MR was identified in 12% of patients, complex bileaflet myxomatous disease in 31%, and specific scallop disease in 55%. Three-dimensional TEE image acquisition was performed in a short period of time (60 +/- 18 seconds) and was feasible in all patients, with optimal (36%) or good (33%) imaging quality in the majority of cases. Three-dimensional TEE imaging was superior to 2D TEE imaging in the diagnosis of P1, A2, A3, and bileaflet disease (P < .05). CONCLUSIONS: Real-time 3D transesophageal echocardiography is a feasible method for identifying specific MV pathology in the setting of complex disease and can be expeditiously used in the intraoperative evaluation of patients undergoing MV repair.