Hemal Gada

Cleveland Clinic, Cleveland, OH, United States

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Publications (8)35.11 Total impact

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    Circulation 04/2013; 127(14):1536-7. · 15.20 Impact Factor
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    ABSTRACT: BACKGROUND: In the setting of chronic stable angina, successful percutaneous coronary intervention (PCI) of chronic total occlusions (CTO) has been shown to produce significant symptom improvement with some evidence for survival benefit. However, the economic basis for this procedure has not been established compared with optimal medical treatment (OMT) of chronic stable angina. OBJECTIVE: The aim of this study was to determine the cost-effectiveness of CTO-PCI in chronic stable angina using a Markov model. DESIGN: The transition probabilities, utilities and costs related to CTO-PCI and OMT used to inform the model were derived from literature and our experience. Implications with respect to cost and quality of life were calculated. Sensitivity analyses were based on factors noted to influence model outcome. RESULTS: In the reference case, mean age 60 years, rate of successful CTO-PCI 67.9%, and mean transition probabilities, utilities and costs as defined by literature and clinical experience, the strategy of CTO-PCI incurred higher costs relative to OMT (US$31 512 vs US$27 805), but also accumulated greater quality-adjusted life-years (QALYs) (2.38 vs 1.99), yielding a cost-effectiveness ratio of US$9505 per QALY. Sensitivity analyses showed the utility of OMT and utilities postsuccessful and postunsuccessful CTO-PCI to be the most influential drivers of outcome. Procedural success held limited influence over model outcome at particular utility threshold values. CONCLUSIONS: On the basis of the supporting evidence, this decision-analytic model suggests that CTO-PCI is cost-effective in a patient population with severe symptoms. Quality-of-life metrics should be employed in future appropriateness criteria developed for CTO-PCI.
    Heart (British Cardiac Society) 10/2012; · 5.01 Impact Factor
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    ABSTRACT: Background- The risks of repeat thoracotomy can be reduced if thoracic multidetector computed tomographic angiography (CTA) is used to guide preventive surgical strategies (PSS: peripheral cardiopulmonary bypass, circulatory arrest, and nonmedian sternotomy). We sought to define the cost-effectiveness of CTA using a Markov model. Methods and Results- We studied outcomes and costs of CTA and non-CTA strategies in a modeled cohort of 10 000 patients undergoing redo coronary artery bypass grafting. Rates of PSS implementation were anticipated to follow identification of risk by CTA. Transitions, costs, and utilities were informed by our experience and the literature. Sensitivity analyses included testing a range of costs of CTA and PSS on model outcome. In the reference case, cost and quality-adjusted life years accrued with the use of CTA ($74 869, 4.63 quality-adjusted life-years) were slightly higher than nonuse ($73 471, 4.59 quality-adjusted life-years), yielding an incremental cost-effectiveness ratio of $34 950/quality-adjusted life-years. Cost of PSS (equipment and operating time) was the most significant determinant of incremental cost-effectiveness ratio. In the reference case (cost of CTA ≈$300), identification and avoidance of potential procedural difficulties with CTA rendered it cost-effective if the cost of PSS was <$12 000. Across a range of CTA costs, incremental cost-effectiveness ratio was not materially influenced by outcomes across a broad range of imputed values. Conclusions- The cost of CTA appears justified in the setting of isolated reoperative coronary artery bypass grafting, because it aids in appropriate selection of PSS. The cost-effectiveness of this imaging seems more influenced by the costs of subsequent PSS than by the cost of CTA.
    Circulation Cardiovascular Quality and Outcomes 08/2012; 5(5):705-10. · 5.66 Impact Factor
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    ABSTRACT: The incremental cost-effectiveness of transapical transcatheter aortic valve implantation (TAVI) is ill-defined in high-risk patients where aortic valve replacement (AVR) is an option, and has not been ascertained outside a randomized controlled trial. We developed a Markov model to examine the progression of patients between health states, defined as peri- and post-procedural, post-complication, and death. The mean and variance of risks, transition probabilities, utilities and cost of transapical TAVI, high-risk AVR, and medical management were derived from analysis of relevant registries. Outcome and cost were derived from 10,000 simulations. Sensitivity analyses further evaluated the impact of mortality, stroke, and other commonly observed outcomes. In the reference case, both transapical TAVI and high-risk AVR and TAVI were cost-effective when compared to medical management ($44,384/QALY and $42,637/QALY, respectively). Transapical TAVI failed to meet accepted criteria for incremental cost-effectiveness relative to AVR, which was the dominant strategy. In sensitivity analyses, the mortality rates related to the two strategies, the utilities post-AVR and post-transapical TAVI, and the cost of transapical TAVI, were the main drivers of model outcome. Transapical TAVI did not satisfy current metrics of incremental cost-effectiveness relative to high-risk AVR in the reference case. However, it may provide net health benefits at acceptable cost in selected high-risk patients among whom AVR is the standard intervention.
    Annals of cardiothoracic surgery. 07/2012; 1(2):145-55.
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    ABSTRACT: Introduction Transcatheter approaches for management of aortic stenosis (AS) have revolutionized the treatment of AS in several patient populations. In patients of high, but not prohibitive, surgical risk, TAVI appears to provide similar outcomes to surgical aortic valve replacement (AVR), as demonstrated by the Placement of Aortic Transcatheter Valve (PARTNER) Cohort A (1). Analysis from this trial has determined that transfemoral, but not transapical, transcatheter aortic valve implantation (TAVI) is incrementally cost-effective relative to AVR. The avoidance of bias in prospective randomized controlled trials have led these protocols to be considered the reference standard with respect to defining the effectiveness of therapies. However, concerns about external validity may arise if aspects of the trial differ from standard practice (2). As variations in the apparent effect of TAVI may be modulated by the prevalence and effect of co-morbid disease, stricter inclusion/exclusion criteria in this circumstance may lead to potential inflation of relative benefit (3). Therefore, despite the risk of selection bias, prospective, registry data may provide insights additional Background: The incremental cost-effectiveness of transapical transcatheter aortic valve implantation
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    ABSTRACT: Comparisons between transcatheter aortic valve implantation without replacement (TAVI) and tissue aortic valve replacement (AVR) in clinical trials might not reflect the outcomes in standard clinical practice. This could have important implications for the relative cost-effectiveness of these alternatives for management of severe aortic stenosis in high-risk patients for whom surgery is an option. The mean and variance of risks, transition probabilities, utilities, and cost of TAVI, AVR, and medical management derived from observational studies were entered into a Markov model that examined the progression of patients between relevant health states. The outcomes and cost were derived from 10,000 simulations. Sensitivity analyses were based on variations in the likelihood of mortality, stroke, and other commonly observed outcomes. Both TAVI and AVR were cost-effective compared to medical management. In the reference case (age 80 years, the perioperative TAVI and AVR mortality was 6.9% vs 9.8%, and annual mortality was 21% vs 24%), the utility of TAVI was greater than that of AVR (1.78 vs 1.72 quality-adjusted life years) and the lifetime cost of TAVI exceeded that of AVR ($59,503 vs $56,339). The incremental cost-effectiveness ratio was $52,773/quality-adjusted life years. Threshold analyses showed that variation in the probabilities of perioperative and annual mortality after AVR and after TAVI and annual stroke after TAVI were important determinants of the favored strategy. Sensitivity analyses defined the thresholds at which TAVI or AVR was the preferred strategy with regard to health outcomes and cost. In conclusion, TAVI satisfies current metrics of cost-effectiveness relative to AVR and might provide net health benefits at acceptable cost for selected high-risk patients among whom AVR is the current procedure of choice.
    The American journal of cardiology 02/2012; 109(9):1326-33. · 3.58 Impact Factor
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    ABSTRACT: BACKGROUND- Traditional management of severe aortic stenosis (AS) is based on delay in aortic valve replacement (AVR) until the development of symptoms. Surgery for asymptomatic AS has been proposed to reduce the small risk of sudden death before AVR and avoid heart failure (HF) after AVR. Because a trial to compare these options is unlikely, we developed a Markov model to inform the choice between immediate surgery and watchful waiting in asymptomatic AS. METHODS AND RESULTS- We defined health states as preoperative, postoperative, postcomplication, and death. We calculated the implications of watchful waiting, tissue and mechanical AVR-based on risks, transitions, utilities, and cost derived from literature review. Further analyses evaluated situations thought to favor immediate surgery and watchful waiting. Sensitivity analyses were based on the likelihood of preoperative death and HF in follow-up. In the reference case (age, 65 years; post-AVR utility, 0.9; annualized pre-AVR mortality, 1%; and post-AVR HF, 11.3%), the utility of watchful waiting was superior to that of immediate mechanical or tissue AVR (quality-adjusted life-years, 7.4 versus 5.3 versus 5.3, respectively), and the cost was less than immediate surgery. Sensitivity analyses showed immediate surgery was not likely to be more effective regardless of the yearly probability of post-AVR HF in the watchful waiting group (range, 0% to 80%). Immediate surgery was likely to be effective when pre-AVR annual mortality reached 13%. CONCLUSIONS- Immediate surgery in asymptomatic severe AS does not improve outcomes unless risk of sudden death pre-AVR and HF after AVR are higher than currently reported.
    Circulation Cardiovascular Quality and Outcomes 08/2011; 4(5):541-8. · 5.66 Impact Factor
  • Hemal Gada, Thomas H. Marwick
    Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/2011; 57(14).