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Featured researches published by Peter C. Block.


The New England Journal of Medicine | 1998

Reduction of Plasma Homocyst(e)ine Levels by Breakfast Cereal Fortified with Folic Acid in Patients with Coronary Heart Disease

M.R. Malinow; Paul Barton Duell; David L. Hess; Peter H. Anderson; Warren D. Kruger; Beverley E. Phillipson; Robert A. Gluckman; Peter C. Block; Barbara M. Upson

BACKGROUND The Food and Drug Administration (FDA) has recommended that cereal-grain products be fortified with folic acid to prevent congenital neural-tube defects. Since folic acid supplementation reduces levels of plasma homocyst(e)ine, or plasma total homocysteine, which are frequently elevated in arterial occlusive disease, we hypothesized that folic acid fortification might reduce plasma homocyst(e)ine levels. METHODS To test this hypothesis, we assessed the effects of breakfast cereals fortified with three levels of folic acid, and also containing the recommended dietary allowances of vitamins B6 and B12, in a randomized, double-blind, placebo-controlled, crossover trial in 75 men and women with coronary artery disease. RESULTS Plasma folic acid increased and plasma homocyst(e)ine decreased proportionately with the folic acid content of the breakfast cereal. Cereal providing 127 microg of folic acid daily, approximating the increased daily intake that may result from the FDAs enrichment policy, increased plasma folic acid by 31 percent (P=0.045) but decreased plasma homocyst(e)ine by only 3.7 percent (P= 0.24). However, cereals providing 499 and 665 microg of folic acid daily increased plasma folic acid by 64.8 percent (P<0.001) and 105.7 percent (P=0.001), respectively, and decreased plasma homocyst(e)ine by 11.0 percent (P<0.001) and 14.0 percent (P=0.001), respectively. CONCLUSIONS Cereal fortified with folic acid has the potential to increase plasma folic acid levels and reduce plasma homocyst(e)ine levels. Further clinical trials are required to determine whether folic acid fortification may prevent vascular disease. Until then, our results suggest that folic acid fortification at levels higher than that recommended by the FDA may be warranted.


Journal of the American College of Cardiology | 2002

A contemporary overview of percutaneous coronary interventions: The American College of Cardiology–National Cardiovascular Data Registry (ACC–NCDR)

H. Vernon Anderson; Richard E. Shaw; Ralph G. Brindis; Kathleen Hewitt; Ronald J. Krone; Peter C. Block; Charles R. McKay; William S. Weintraub

The American College of Cardiology (ACC) established the National Cardiovascular Data Registry (ACC-NCDR) to provide a uniform and comprehensive database for analysis of cardiovascular procedures across the country. The initial focus has been the high-volume, high-profile procedures of diagnostic cardiac catheterization and percutaneous coronary intervention (PCI). Several large-scale multicenter efforts have evaluated diagnostic catheterization and PCI, but these have been limited by lack of standard definitions and relatively nonuniform data collection and reporting methods. Both clinical and procedural data, and adverse events occurring up to hospital discharge, were collected and reported according to uniform guidelines using a standard set of 143 data elements. Datasets were transmitted quarterly to a central facility for quality-control screening, storage and analysis. This report is based on PCI data collected from January 1, 1998, through September 30, 2000.A total of 139 hospitals submitted data on 146,907 PCI procedures. Of these, 32% (46,615 procedures) were excluded because data did not pass quality-control screening. The remaining 100,292 procedures (68%) were included in the analysis set. Average age was 64 +/- 12 years; 34% were women, 26% had diabetes mellitus, 29% had histories of prior myocardial infarction (MI), 32% had prior PCI and 19% had prior coronary bypass surgery. In 10% the indication for PCI was acute MI < or =6 h from onset, while in 52% it was class II to IV or unstable angina. Only 5% of procedures did not have a class I indication by ACC criteria, but this varied by hospital from a low of 0 to a high of 38%. A coronary stent was placed in 77% of procedures, but this varied by hospital from a low of 0 to a high of 97%. The frequencies of in-hospital Q-wave MI, coronary artery bypass graft surgery and death were 0.4%, 1.9% and 1.4%, respectively. Mortality varied by hospital from a low of 0 to a high of 4.2%. This report presents the first data collected and analyzed by the ACC-NCDR. It portrays a contemporary overview of coronary interventional practices and outcomes, using uniform data collection and reporting standards. These data reconfirm overall acceptable results that are consistent with other reported data, but also confirm large variations between individual institutions.


Journal of the American College of Cardiology | 2002

Development of a risk adjustment mortality model using the American College of Cardiology–National Cardiovascular Data Registry (ACC–NCDR) experience: 1998–2000

Richard E. Shaw; H.Vernon Anderson; Ralph G. Brindis; Ronald J. Krone; Lloyd W. Klein; Charles R. McKay; Peter C. Block; Leslee J Shaw; Kathleen Hewitt; William S. Weintraub

OBJECTIVES We sought to develop and evaluate a risk adjustment model for in-hospital mortality following percutaneous coronary intervention (PCI) procedures using data from a large, multi-center registry. BACKGROUND The 1998-2000 American College of Cardiology-National Cardiovascular Data Registry (ACC-NCDR) dataset was used to overcome limitations of prior risk-adjustment analyses. METHODS Data on 100,253 PCI procedures collected at the ACC-NCDR between January 1, 1998, and September 30, 2000, were analyzed. A training set/test set approach was used. Separate models were developed for presentation with and without acute myocardial infarction (MI) within 24 h. RESULTS Factors associated with increased risk of PCI mortality (with odds ratios in parentheses) included cardiogenic shock (8.49), increasing age (2.61 to 11.25), salvage (13.38) urgent (1.78) or emergent PCI (5.75), pre-procedure intra-aortic balloon pump insertion (1.68), decreasing left ventricular ejection fraction (0.87 to 3.93), presentation with acute MI (1.31), diabetes (1.41), renal failure (3.04), chronic lung disease (1.33); treatment approaches including thrombolytic therapy (1.39) and non-stent devices (1.64); and lesion characteristics including left main (2.04), proximal left anterior descending disease (1.97) and Society for Cardiac Angiography and Interventions lesion classification (1.64 to 2.11). Overall, excellent discrimination was achieved (C-index = 0.89) and application of the model to high-risk patient groups demonstrated C-indexes exceeding 0.80. Patient factors were more predictive in the MI model, while lesion and procedural factors were more predictive in the analysis of non-MI patients. CONCLUSIONS A risk adjustment model for in-hospital mortality after PCI was successfully developed using a contemporary multi-center registry. This model is an important tool for valid comparison of in-hospital mortality after PCI.


Jacc-cardiovascular Interventions | 2009

Percutaneous Left Atrial Appendage Occlusion for Patients in Atrial Fibrillation Suboptimal for Warfarin Therapy: 5-Year Results of the PLAATO (Percutaneous Left Atrial Appendage Transcatheter Occlusion) Study

Peter C. Block; Steven Burstein; Paul N. Casale; Paul Kramer; Paul S. Teirstein; David O. Williams; Mark Reisman

OBJECTIVES The aim of this study was to determine 5-year clinical status for patients treated with percutaneous left atrial appendage transcatheter occlusion with the PLAATO (Percutaneous Left Atrial Appendage Transcatheter Occlusion) system. BACKGROUND Anticoagulation reduces thromboembolism among patients with nonvalvular atrial fibrillation (AF). However, warfarin is a challenging medication due to risks of inadequate anticoagulation and bleeding. Thus, PLAATO was evaluated as a treatment strategy for nonwarfarin candidate patients with AF at high risk for stroke. METHODS Sixty-four patients with permanent or paroxysmal AF participated in this observational, multicenter prospective study. Primary end points were: new major or minor stroke, cardiac or neurological death, myocardial infarction, or requirement for cardiovascular surgery related to the procedure within 1 month of the index procedure. Patients were followed for up to 5 years. RESULTS Thirty-day freedom from major adverse events rate was 98.4% (95% confidence interval: 90.89% to >99.99%). One patient, who did not receive a PLAATO implant, experienced 2 events within 30 days (cardiovascular surgery, death). Treatment success was 100% 1 month after device implantation. At 5-year follow-up, there were 7 deaths, 5 major strokes, 3 minor strokes, 1 cardiac tamponade requiring surgery, 1 probable cerebral hemorrhage/death, and 1 myocardial infarction. Only 1 event (cardiac tamponade) was adjudicated as related to the implant procedure. After up to 5 years of follow-up, the annualized stroke/transient ischemic attack (TIA) rate was 3.8%. The anticipated stroke/TIA rate (with the CHADS(2) scoring method) was 6.6%/year. CONCLUSIONS The PLAATO system is safe and effective. At 5-year follow-up the annualized stroke/TIA rate in our patients was 3.8%/year, less than predicted by the CHADS(2) scoring system.


Jacc-cardiovascular Interventions | 2014

Comparison of transfemoral transcatheter aortic valve replacement performed in the catheterization laboratory (minimalist approach) versus hybrid operating room (standard approach): outcomes and cost analysis.

Vasilis Babaliaros; Chandan Devireddy; Stamatios Lerakis; Robert Leonardi; Sebastian Iturra; Kreton Mavromatis; Bradley G. Leshnower; Robert A. Guyton; Mihir Kanitkar; Patricia Keegan; Amy Simone; James Stewart; Nima Ghasemzadeh; Peter C. Block; Vinod H. Thourani

OBJECTIVES The aim of this study was to compare transfemoral transcatheter aortic valve replacement (TF TAVR) performed in a catheterization laboratory (minimalist approach [MA]) with TF TAVR performed in a hybrid operating room (standard approach [SA]). BACKGROUND A MA-TF TAVR can be performed without general anesthesia, transesophageal echocardiography, or a surgical hybrid room. The outcomes and cost of MA-TF TAVR compared with those of the SA have not been described. METHODS Patients who underwent elective, percutaneous TF TAVR using the Edwards Sapien valve (Edwards Lifesciences, Irvine, California) were studied. Baseline characteristics, outcomes, and hospital costs of MA-TF TAVR and SA-TF TAVR were compared. RESULTS A total of 142 patients were studied (MA-TF TAVR, n = 70 and SA-TF TAVR, n = 72). There were no differences in baseline comorbidities (Society of Thoracic Surgeons score, 10.6 ± 4.3 vs. 11.4 ± 5.8; p = 0.35). All procedures in the MA-TF TAVR group were successful; 1 patient was intubated. Three patients in the SA-TF TAVR group had procedure-related death. Procedure room time (150 ± 48 min vs. 218 ± 56 min, p < 0.001), total intensive care unit time (22 h vs. 28 h, p < 0.001), length of stay from procedure to discharge (3 days vs. 5 days, p < 0.001), and cost (


Catheterization and Cardiovascular Interventions | 2007

Prevention of contrast induced nephropathy: Recommendations for the high risk patient undergoing cardiovascular procedures

Marc J. Schweiger; Charles E. Chambers; Charles J. Davidson; Shaoheng Zhang; James C. Blankenship; Narinder P. Bhalla; Peter C. Block; John P. Dervan; Christine Gasperetti; Lowell Gerber; Neal S. Kleiman; Ronald J. Krone; William J. Phillips; Robert M. Siegel; Barry F. Uretsky; Warren K. Laskey

45,485 ± 14,397 vs.


Journal of the American College of Cardiology | 2002

Percutaneous Coronary Interventions in Octogenarians in the American College of Cardiology-National Cardiovascular Data Registry Development of a Nomogram Predictive of In-Hospital Mortality

Lloyd W. Klein; Peter C. Block; Ralph G. Brindis; Charles R. McKay; Ben D. McCallister; Michael J. Wolk; William S. Weintraub

55,377 ± 22,587, p < 0.001) were significantly less in the MA-TF TAVR group. Mortality at 30 days was not significantly different in the MA-TF TAVR group (0 vs. 6%, p = 0.12) and 30-day stroke/transient ischemic attack was similar (4.3% vs. 1.4%, p = 0.35). Moderate or severe paravalvular leak and device success were similar in the MA-TF TAVR and SA-TF TAVR groups (3% vs. 5.8%, p = 0.4 and 90% vs. 88%, p = 0.79, respectively) at 30 days. At a median follow-up of 435 days, there was no significant difference in survival (MA-TF TAVR, 83% vs. SA-TF TAVR, 82%; p = 0.639). CONCLUSIONS MA-TF TAVR can be performed with minimal morbidity and mortality and equivalent effectiveness compared with SA-TF TAVR. The shorter length of stay and lower resource use with MA-TF TAVR significantly lowers hospital costs.


The Cardiology | 2007

State of the Art Percutaneous Intervention for the Treatment of Valvular Heart Disease: A Review of the Current Technologies and Ongoing Research in the Field of Percutaneous Valve Replacement and Repair

Vasilis Babaliaros; Peter C. Block

Contrast induced nephropathy (CIN) is the third leading cause of hospital aquired renal failure and is associated with significant morbidity and mortality. Chronic kidney disease is the primary predisposing factor for CIN. As estimated glomerular filtration rate <60 ml/1.73 m2 represents significant renal dysfunction and defines patients at high risk. Modifiable risk factors for CIN include hydration status, the type and amount of contrast, use of concomitant nephrotoxic agents and recent contrast administration. The cornerstone of CIN prevention, in both the high and low risk patients, is adequate parenteral volume repletion. In the patient at increased risk for CIN it is often appropriate to withhold potentially nephrotoxic medications, and consider the use of n‐acetylcysteine. In patients at increased risk for CIN the use of low or iso‐osomolar contrast agents should be utilized and strategies employed to minimize contrast volume. In these patients serum creatinine should be obtained forty‐eight hours post procedure and it is often appropriate to continue withholding medications such as metformin or non steroidal anti‐inflammatories until renal function returns to normal.


American Journal of Cardiology | 2003

Evaluation of the American College of Cardiology/American Heart Association and the Society for Coronary Angiography and Interventions lesion classification system in the current “stent era” of coronary interventions (from the ACC-National Cardiovascular Data Registry)

Ronald J. Krone; Richard E. Shaw; Lloyd W. Klein; Peter C. Block; H. Vernon Anderson; William S. Weintraub; Ralph G. Brindis; Charles R. McKay

OBJECTIVES We sought to evaluate the results of percutaneous coronary intervention (PCI) in elderly patients in contemporary practice. BACKGROUND Prior studies of PCI in the elderly population demonstrate increased in-hospital mortality, but these studies are limited by small population size. METHODS Using the American College of Cardiology-National Cardiovascular Data Registry (ACC-NCDR) of 100,253 patients, the in-hospital outcomes in all 8,828 PCI procedures performed on octogenarians were evaluated. Patients underwent PCI between 1998 and 2000 at over 145 participating centers. RESULTS The mean age was 83.72 +/- 3.02 years, with female preponderance (53%). The PCI was considered angiographically successful in 93%, stents were placed in 75%, and the post-PCI length of stay was 3.3 +/- 5.1 days. Overall in-hospital mortality was 3.77% but was only 1.35% in PCI without recent myocardial infarction (MI) within one week (p < 0.0001). Patients having PCI within 6 h of the onset of their MI had an increase in mortality tenfold (13.79%) compared with patients without a recent MI (p < 0.0001). All groups that were defined based on time of PCI after MI onset up to seven days had increased mortality (all p < 0.0001). Older age (odds ratio [OR] of 1.03 per incremental year), depressed ejection fraction (EF) (OR 0.69 per 10 points for EF <60%), and time of PCI after MI onset (<6 h, OR 6.87; 6 to 24 h, OR 5.66; 24 h to one week, OR 2.93) were most strongly predictive of outcome by multivariate analysis. The predicted mortality from the multivariate model correlated well with the observed in-hospital mortality up to 20% mortality. A 254-point nomogram was constructed employing the logistic model using a weighted point system. CONCLUSIONS In patients > or = 80 years old, PCI has good success and acceptable mortality. The presence of an acute or recent MI substantially increases the risk of in-hospital death.


American Journal of Cardiology | 2002

Comparison of in-hospital and one-year outcomes in patients with and without diabetes mellitus undergoing percutaneous catheter intervention (from the National Heart, Lung, and Blood Institute Dynamic Registry) ☆

Warren K. Laskey; Faith Selzer; Helen Vlachos; Janet Johnston; Alice K. Jacobs; Spencer B. King; David R. Holmes; John S. Douglas; Peter C. Block; Robert L. Wilensky; David O. Williams; Katherine M. Detre

Technical developments in valvular intervention culminated in the first percutaneous valve replacement in the pulmonary position (2000) followed by replacement in the aortic position (2002). More recently, with the proven feasibility of percutaneous mitral valve repair, interventional cardiologists and cardiothoracic surgeons have begun to develop a new subspecialty dedicated to the percutaneous treatment of valvular disease. This review describes the clinical status of the current field, the applicability and limitations of new technologies, and the upcoming devices that will soon reach Phase I clinical trials.

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