Nirat Beohar

Clinical Applications of Blood-Derived and Marrow-Derived Stem Cells for Nonmalignant Diseases

CONTEXT Stem cell therapy is rapidly developing and has generated excitement and promise as well as confusion and at times contradictory results in the lay and scientific literature. Many types of stem cells show great promise, but clinical application has lagged due to ethical concerns or difficulties in harvesting or safely and efficiently expanding sufficient quantities. In contrast, clinical indications for blood-derived (from peripheral or umbilical cord blood) and bone marrow-derived stem cells, which can be easily and safely harvested, are rapidly increasing. OBJECTIVE To summarize new, nonmalignant, nonhematologic clinical indications for use of blood- and bone marrow-derived stem cells. EVIDENCE ACQUISITION Search of multiple electronic databases (MEDLINE, EMBASE, Science Citation Index), US Food and Drug Administration [FDA] Drug Site, and National Institutes of Health Web site to identify studies published from January 1997 to December 2007 on use of hematopoietic stem cells (HSCs) in autoimmune, cardiac, or vascular diseases. The search was augmented by hand searching of reference lists in clinical trials, review articles, proceedings booklets, FDA reports, and contact with study authors and device and pharmaceutical companies. EVIDENCE SYNTHESIS Of 926 reports identified, 323 were examined for feasibility and toxicity, including those with small numbers of patients, interim or substudy reports, and reports on multiple diseases, treatment of relapse, toxicity, mechanism of action, or stem cell mobilization. Another 69 were evaluated for outcomes. For autoimmune diseases, 26 reports representing 854 patients reported treatment-related mortality of less than 1% (2/220 patients) for nonmyeloablative, less than 2% (3/197) for dose-reduced myeloablative, and 13% (13/100) for intense myeloablative regimens, ie, those including total body irradiation or high-dose busulfan. While all trials performed during the inflammatory stage of autoimmune disease suggested that transplantation of HSCs may have a potent disease-remitting effect, remission duration remains unclear, and no randomized trials have been published. For reports involving cardiovascular diseases, including 17 reports involving 1002 patients with acute myocardial infarction, 16 involving 493 patients with chronic coronary artery disease, and 3 meta-analyses, the evidence suggests that stem cell transplantation performed in patients with coronary artery disease may contribute to modest improvement in cardiac function. CONCLUSIONS Stem cells harvested from blood or marrow, whether administered as purified HSCs or mesenchymal stem cells or as an unmanipulated or unpurified product can, under appropriate conditions in select patients, provide disease-ameliorating effects in some autoimmune diseases and cardiovascular disorders. Clinical trials are needed to determine the most appropriate cell type, dose, method, timing of delivery, and adverse effects of adult HSCs for these and other nonmalignant disorders.

Predictors of Poor Outcomes After Transcatheter Aortic Valve Replacement Results From the PARTNER (Placement of Aortic Transcatheter Valve) Trial

Background— Transcatheter aortic valve replacement (TAVR) is a less invasive option for treatment of high-risk patients with severe aortic stenosis. We sought to identify patients at high risk for poor outcome after TAVR using a novel definition of outcome that integrates quality of life with mortality. Methods and Results— Among 2137 patients who underwent TAVR in the PARTNER (Placement of Aortic Transcatheter Valve) trial or its associated continued access registry, quality of life was assessed with the Kansas City Cardiomyopathy Questionnaire–Overall Summary Scale (KCCQ-OS; range 0–100, where a higher score equates to a better quality of life) at baseline and at 1, 6, and 12 months after TAVR. A poor 6-month outcome (defined as death, KCCQ-OS score <45, or ≥10-point decrease in KCCQ-OS score compared with baseline) occurred in 704 patients (33%). Using a split-sample design, we developed a multivariable model to identify a parsimonious set of covariates to identify patients at high risk for poor outcome. The model demonstrated moderate discrimination (c-index=0.66) and good calibration with the observed data, performed similarly in the separate validation cohort (c-index=0.64), and identified 211 patients (10% of the population) with a ≥50% likelihood of a poor outcome after TAVR. A second model that explored predictors of poor outcome at 1 year identified 1102 patients (52%) with ≥50% likelihood and 178 (8%) with ≥70% likelihood of a poor 1-year outcome after TAVR. Conclusions— Using a large, multicenter cohort, we have developed and validated predictive models that can identify patients at high risk for a poor outcome after TAVR. Although model discrimination was moderate, these models may help guide treatment choices and offer patients realistic expectations of outcomes based on their presenting characteristics. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00530894.Background— Transcatheter aortic valve replacement (TAVR) is a less invasive option for treatment of high-risk patients with severe aortic stenosis. We sought to identify patients at high risk for poor outcome after TAVR using a novel definition of outcome that integrates quality of life with mortality. Methods and Results— Among 2137 patients who underwent TAVR in the PARTNER (Placement of Aortic Transcatheter Valve) trial or its associated continued access registry, quality of life was assessed with the Kansas City Cardiomyopathy Questionnaire–Overall Summary Scale (KCCQ-OS; range 0–100, where a higher score equates to a better quality of life) at baseline and at 1, 6, and 12 months after TAVR. A poor 6-month outcome (defined as death, KCCQ-OS score <45, or ≥10-point decrease in KCCQ-OS score compared with baseline) occurred in 704 patients (33%). Using a split-sample design, we developed a multivariable model to identify a parsimonious set of covariates to identify patients at high risk for poor outcome. The model demonstrated moderate discrimination ( c -index=0.66) and good calibration with the observed data, performed similarly in the separate validation cohort ( c -index=0.64), and identified 211 patients (10% of the population) with a ≥50% likelihood of a poor outcome after TAVR. A second model that explored predictors of poor outcome at 1 year identified 1102 patients (52%) with ≥50% likelihood and 178 (8%) with ≥70% likelihood of a poor 1-year outcome after TAVR. Conclusions— Using a large, multicenter cohort, we have developed and validated predictive models that can identify patients at high risk for a poor outcome after TAVR. Although model discrimination was moderate, these models may help guide treatment choices and offer patients realistic expectations of outcomes based on their presenting characteristics. Clinical Trial Registration— URL: . Unique identifier: [NCT00530894][1]. # CLINICAL PERSPECTIVE {#article-title-31} [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00530894&atom=%2Fcirculationaha%2F129%2F25%2F2682.atom

Rebuilding the Damaged Heart : The Potential of Cytokines and Growth Factors in the Treatment of Ischemic Heart Disease

Cytokine therapy promises to provide a noninvasive treatment option for ischemic heart disease. Cytokines are thought to influence angiogenesis directly via effects on endothelial cells or indirectly through progenitor cell-based mechanisms or by activating the expression of other angiogenic agents. Several cytokines mobilize progenitor cells from the bone marrow or are involved in the homing of mobilized cells to ischemic tissue. The recruited cells contribute to myocardial regeneration both as a structural component of the regenerating tissue and by secreting angiogenic or antiapoptotic factors, including cytokines. To date, randomized, controlled clinical trials have not reproduced the efficacy observed in pre-clinical and small-scale clinical investigations. Nevertheless, the list of promising cytokines continues to grow, and combinations of cytokines, with or without concurrent progenitor cell therapy, warrant further investigation.

Determinants and Outcomes of Acute Transcatheter Valve-in-Valve Therapy or Embolization: A Study of Multiple Valve Implants in the U.S. PARTNER Trial (Placement of AoRTic TraNscathetER Valve Trial Edwards SAPIEN Transcatheter Heart Valve)

OBJECTIVES This study investigated the determinants and outcomes of acute insertion of a second transcatheter prosthetic valve (TV) within the first (TV-in-TV) or transcatheter valve embolization (TVE) after transcatheter aortic valve replacement (TAVR). BACKGROUND TAVR failure can occur with both TV-in-TV and TVE as a consequence of TAVR malpositioning. Only case reports and limited series pertaining to these complications have been reported to date. METHODS Patients undergoing TAVR in the PARTNER (Placement of AoRTic TraNscathetER Valve Trial Edwards SAPIEN Transcatheter Heart Valve) randomized trial (cohorts A and B) and accompanying registries were studied. Data were dichotomized for those with and without TV-in-TV or TVE, respectively. RESULTS From a total of 2,554 consecutive patients, 63 (2.47%) underwent TV-in-TV and 26 (1.01%) TVE. The indication for TV-in-TV was significant aortic regurgitation in most patients, often due not only to malpositioning but also to leaflet dysfunction. Despite similar aortic valve function on follow-up echoes, TV-in-TV was an independent predictor of 1-year cardiovascular mortality (hazard ratio [HR]: 1.86, 95% confidence interval [CI]: 1.03 to 3.38, p = 0.041), with a nonsignificant trend toward greater all-cause mortality (HR: 1.43, 95% CI: 0.88 to 2.33, p = 0.15). Technical and anatomical reasons accounted for most cases of TVE. A multivariable analysis found TVE to be an independent predictor of 1-year mortality (HR: 2.68, 95% CI: 1.34 to 5.36, p = 0.0055) but not cardiovascular mortality (HR: 1.30, 95% CI: 0.48 to 3.52, p = 0.60). CONCLUSIONS Acute TV-in-TV and TVE are serious sequelae of TAVR, often resulting in multiple valve implants. They carry an excess of mortality and are caused by anatomic and technical factors, which may be avoidable with judicious procedural planning.

Drug-Eluting Versus Bare-Metal Stents in Unprotected Left Main Coronary Artery Stenosis: A Meta-Analysis

OBJECTIVES We undertook a meta-analysis to assess outcomes for drug-eluting stents (DES) and bare-metal stents (BMS) in percutaneous coronary intervention for unprotected left main coronary artery (ULMCA) stenosis. BACKGROUND Uncertainty exists regarding the relative performance of DES versus BMS in percutaneous coronary intervention for unprotected left main coronary stenosis. METHODS Of a total of 838 studies, 44 met inclusion criteria (n = 10,342). The co-primary end points were mortality, myocardial infarction (MI), target vessel/lesion revascularization (TVR/TLR), and major adverse cardiac events (MACE: mortality, MI, TVR/TLR). RESULTS Event rates for DES and BMS were calculated at 6 to 12 months, at 2 years, and at 3 years. Crude event rates at 3 years were mortality (8.8% and 12.7%), MI (4.0% and 3.4%), TVR/TLR (8.0% and 16.4%), and MACE (21.4% and 31.6%). Nine studies were included in a comparative analysis (n = 5,081). At 6 to 12 months the adjusted odds ratio (OR) for DES versus BMS were: mortality 0.94 (95% confidence interval [CI]: 0.06 to 15.48; p = 0.97), MI 0.64 (95% CI: 0.19 to 2.17; p = 0.47), TVR/TLR 0.10 (95% CI: 0.01 to 0.84; p = 0.01), and MACE 0.34 (95% CI: 0.15 to 0.78; p = 0.01). At 2 years, the OR for DES versus BMS were: mortality 0.42 (95% CI: 0.28 to 0.62; p < 0.01), MI 0.16 (95% CI: 0.01 to 3.53; p = 0.13), and MACE 0.31 (95% CI: 0.15 to 0.66; p < 0.01). At 3 years, the OR for DES versus BMS were: mortality 0.70 (95% CI: 0.53 to 0.92; p = 0.01), MI 0.49 (95% CI: 0.26 to 0.92; p = 0.03), TVR/TLR 0.46 (95% CI: 0.30 to 0.69; p < 0.01), and MACE 0.78 (95% CI: 0.57 to 1.07; p = 0.12). CONCLUSIONS Our meta-analysis suggests that DES is associated with favorable outcomes for mortality, MI, TVR/TLR, and MACE as compared to BMS in percutaneous coronary intervention for unprotected left main coronary artery stenosis.

Contemporary Perioperative Results of Isolated Aortic Valve Replacement for Aortic Stenosis

BACKGROUND Transcatheter aortic valve implantation may become a potential treatment for high-risk patients with aortic stenosis (AS). We analyzed our contemporary series of isolated aortic valve replacement (AVR) for AS to determine implications for patients referred for AVR. METHODS From April 2004 through December 2008, 190 patients (mean age, 68 years; 68% men) underwent isolated AVR for AS. Mean ejection fraction was 0.58. Sixty-one percent underwent minimally invasive AVR and 18% were reoperations. Twenty-one percent were aged 80 years or older, and 34% were in New York Heart Association functional class III-IV. Estimated operative mortality was 3.6%. RESULTS Thirty-day mortality was 0%. One in-hospital death (0.5%) occurred from complications of an esophageal perforation. Reoperation for bleeding occurred in 4.7%. Acute renal failure developed in 2.1%. Actuarial survival was 97% at 1 year and 94% at 3 years. Hospital length of stay was 7.0 days for patients aged 80 and older vs 5.0 days (p < 0.001), and they were less likely to be discharged to home (50% vs 83%, p < 0.001). CONCLUSIONS Contemporary results show that AVR for AS can be performed with low operative mortality and morbidity, although patients aged 80 years and older are at increased risk of prolonged recovery. Transcatheter aortic valve implantation may be an alternative for high-risk patients, but AVR is still appropriate for low-risk patients. The low risk of AVR supports the argument that asymptomatic patients who have a high likelihood of progression of AS may be considered for earlier surgical referral.

How to Define a Poor Outcome After Transcatheter Aortic Valve Replacement Conceptual Framework and Empirical Observations From the Placement of Aortic Transcatheter Valve (PARTNER) Trial

Background—Transcatheter aortic valve replacement (TAVR) has emerged as a less invasive option for valve replacement of patients with severe aortic stenosis. Although it has been recommended that TAVR should not be offered to patients who will not improve functionally or derive meaningful survival benefit from the procedure, no guidance exists on how best to identify such patients. The first step in this process is to define a poor outcome that can then be used as a foundation for subsequent case identification. We sought to evaluate potential definitions of a poor outcome after TAVR that combine both mortality and quality of life components. Methods and Results—Using data from 463 patients who underwent TAVR as part of the Placement of AoRTic TraNscathetER Valve (PARTNER) trial, we evaluated 6-month mortality and quality of life outcomes using the Kansas City Cardiomyopathy Questionnaire to explore potential definitions of a poor outcome. We then compared the strengths and weaknesses of each potential definition by examining the relationship between baseline and 6-month Kansas City Cardiomyopathy Questionnaire scores for each patient. Based on these analyses, we argue that the most appropriate definition of a poor outcome after TAVR is (1) death, (2) Kansas City Cardiomyopathy Questionnaire overall summary score <45, or (3) Kansas City Cardiomyopathy Questionnaire decrease of ≥10 points, which best reflects a failure to achieve the therapeutic goals of TAVR. Conclusions—Using empirical data on a large number of patients enrolled in the PARTNER trial, we propose a definition for poor outcome after TAVR that combines both mortality and quality of life measures into a single composite end point. Use of this end point (or other similar end points) in future studies can facilitate development of predictive models that may be useful to identify patients who are poor candidates for TAVR and to provide such patients and their families with appropriate expectations of functional recovery after TAVR.

Acute Heart Failure Syndromes and Coronary Perfusion

Acute heart failure syndromes (AHFS), with a high post-discharge mortality and rehospitalization rate, represent a significant public health burden. The treatment of patients hospitalized with AHFS often includes the use of vasoactive medications such as inotropes and vasodilators. Although such agents are frequently used, their safety and efficacy remain controversial. A significant number of patients with heart failure have underlying coronary artery disease and may be at greater risk from hemodynamic alterations that can diminish coronary perfusion. In AHFS, the relationship among vasoactive medications, coronary perfusion, and potential myocardial injury needs further investigation. Newer techniques now available to evaluate coronary perfusion should provide guidance for the evaluation of existing and future vasoactive therapies for AHFS.

A meta-analysis of transcatheter closure of patent foramen ovale versus medical therapy for prevention of recurrent thromboembolic events in patients with cryptogenic cerebrovascular events.

We sought to perform a meta‐analysis of randomized controlled trials (RCTs) comparing percutaneous patent‐foramen‐ovale (PFO) closure with medical therapy for preventing recurrent thromboembolic events after cryptogenic stroke.

Relation Between Six-Minute Walk Test Performance and Outcomes After Transcatheter Aortic Valve Implantation (from the PARTNER Trial)

Functional capacity as assessed by 6-minute walk test distance (6MWTD) has been shown to predict outcomes in selected cohorts with cardiovascular disease. To evaluate the association between 6MWTD and outcomes after transcatheter aortic valve implantation (TAVI) among participants in the Placement of AoRTic TraNscathetER valve (PARTNER) trial, TAVI recipients (n = 484) were stratified into 3 groups according to baseline 6MWTD: unable to walk (n = 218), slow walkers (n = 133), in whom 6MWTD was below the median (128.5 meters), and fast walkers (n = 133) with 6MWTD >128.5 meters. After TAVI, among fast walkers, follow-up 6MWTD decreased by 44 ± 148 meters at 12 months (p <0.02 compared with baseline). In contrast, among slow walkers, 6MWTD improved after TAVI by 58 ± 126 meters (p <0.001 compared with baseline). Similarly, among those unable to walk, 6MWTD distance increased by 66 ± 109 meters (p <0.001 compared with baseline). There were no differences in 30-day outcomes among 6MWTD groups. At 2 years, the rate of death from any cause was 42.5% in those unable to walk, 31.2% in slow walkers, and 28.8% in fast walkers (p = 0.02), driven primarily by differences in noncardiac death. In conclusion, among high-risk older adults undergoing TAVI, baseline 6MWTD does not predict procedural outcomes but does predict long-term mortality. Nonetheless, patients with poor baseline functional status exhibit the greatest improvement in 6MWTD. Additional work is required to identify those with poor functional status who stand to benefit the most from TAVI.