PubMed Health⌕ Search

Biomedical subjects

Gary L Grunkemeier

Publications and source records attributed to Gary L Grunkemeier.

At least 19 recordsLinked to original sources
PubMed2006

Time-related risk of the St. Jude Silzone heart valve.

OBJECTIVE: The St. Jude Medical Silzone heart valve had a silver-impregnated sewing ring designed to reduce the incidence of prosthetic valve endocarditis. Recruitment to the randomized AVERT study comparing Silzone valves with non-Silzone Control valves was stopped because of an increased risk of reoperation for paravalvular leak, but patient follow-up continues. Determining the time-related risk profile of the Silzone valve is important for helping physicians manage the approximately 28,000 patients currently alive with a Silzone valve. METHODS: Between 1998 and 2000, 403 Silzone and 404 Control patients were enrolled in AVERT. As of July 2005, there were 1819 Silzone and 1842 Control patient-years of follow-up (mean 4.5, median 5.1 years). Analysis emphasized the use and interpretation of hazard functions, since they are more meaningful than event-free percentages to currently surviving patients. To this end, instead of Cox regression, which estimates the hazard ratio, assuming it is constant over time, we employed primarily Aalen additive regression, which measures the hazard difference, and produces a plot of it over time. We assessed the risks of major paravalvular leak, endocarditis, bleeding and thrombo-embolism. RESULTS: The Silzone valve had a higher initial risk of major paravalvular leak than Control in the mitral (p=0.02) position, but not in the aortic (p=0.42) position. Analysis of this risk using additive regression, with all valve positions combined, showed that the initial risk due to Silzone lost statistical significance by 2 years and disappeared by 4 years after implant. In the mitral position, the Silzone valve had a higher initial risk of thrombo-embolism plus bleeding than Control; this risk also lost statistical significance by 2 years and subsided to zero by 4 years. The risks for death and endocarditis were similar for Slizone and Control valves. CONCLUSIONS: The additional risks of the Silzone valve, compared to Control, diminish over time and disappear by 4 years after implant. The minimum time after implant of the patients currently alive with Silzone is now well beyond 5 years; thus, these current patients now have a risk profile similar to that of patients with a standard St. Jude valve.

Aged↗
PubMed2006

Comparison of Carpentier-Edwards pericardial and supraannular bioprostheses in aortic valve replacement.

OBJECTIVE: This study aimed at calculating and comparing the long-term outcomes of patients after aortic valve replacement with the Carpentier-Edwards bovine pericardial and porcine supraannular bioprostheses using microsimulation. METHODS: We conducted a meta-analysis of eight studies on the Carpentier-Edwards pericardial valves (2,685 patients, 12,250 patient-years) and five studies on the supraannular valves (3,796 patients, 20,127 patient-years) to estimate the occurrence rates of valve-related events. Eighteen-year follow-up data sets were used to construct age-dependent Weibull curves that described their structural valvular deterioration. The estimates were entered into a microsimulation model, which was used to calculate the outcomes of patients after aortic valve replacement. RESULTS: The annual hazard rates for thrombo-embolism after aortic valve replacement were 1.35% and 1.76% for the pericardial and supraannular valves, respectively. For a 65-year-old male, median time to structural valvular deterioration was 20.1 and 22.2 years while the lifetime risk of reoperation due to structural valvular deterioration was 18.3% and 14.0%, respectively. The life expectancy of the patient was 10.8 and 10.9 years and event-free life expectancy 9.0 and 8.8 years, respectively. CONCLUSIONS: The microsimulation methodology provides insight into the prognosis of a patient after aortic valve replacement with any given valve type. Both the Carpentier-Edwards pericardial and supraannular valve types perform satisfactorily, especially in elderly patients, and show no appreciable difference in long-term outcomes when implanted in the aortic position.

Aged↗
PubMed2006

Homograft implantation techniques in the aortic position: to preserve or replace the aortic root?

BACKGROUND: One determinant of durability of the homograft in the aortic position is the implantation technique. This study uses meta-analytical techniques to evaluate the differences in early and long-term outcomes of patients undergoing aortic homograft implantation with either a root replacement or a root preserving technique. METHODS: A systematic review of the literature (1965-2005) reporting results after homograft implantation in the aortic position with emphasis in the implantation technique was performed. Random and fixed-effects models were used. Cumulative and influential meta-analysis, graphic exploration, and sensitivity analysis were carried out to explain the heterogeneity between studies and to investigate potential publication bias. RESULTS: Eleven studies were included. None of the studies was randomized. There was no significant difference in early mortality between root replacement and root preserving groups (odds ratio = 2.57 with 95% confidence interval [CI] 0.68-9.72 in random-effects model) and the root replacement group had a significantly lower rate of reoperation during long-term follow-up (hazard ratio = 0.55 with 95% CI 0.38-0.80 in random-effects model). Subgroup analysis focusing on patients having the subcoronary technique for homograft implantation showed similar results. Significant heterogeneity between studies can be detected. No publication bias was found. CONCLUSIONS: There was no significant difference in early mortality between root replacement and root preserving groups. However, the root replacement technique group had a significantly lower rate of reoperation during long-term follow-up. Excluding outliers identified in a funnel plot reduced the heterogeneity and reached a similar conclusion.

Aortic Valve↗
PubMed2005

Aborted off-pump coronary artery bypass patients have much worse outcomes than on-pump or successful off-pump patients.

BACKGROUND: Off-pump coronary artery bypass graft (CABG) surgery is purported to reduce perioperative mortality and morbidity compared with on-pump coronary bypass graft surgery. However, the outcomes of patients for whom an off-pump strategy must be changed to an on-pump procedure during surgery have not been extensively studied. METHODS AND RESULTS: The Merged Cardiac Registry (Health Data Research, Inc) contains 70 514 isolated CABG performed from January 1998 to March 2004 in 40 facilities. Among them, 62 634 patients begun and completed on-pump bypass (CPB); 7880 patients begun off-pump, of which 7424 (94.2%) completed off-pump coronary artery bypass (OPCAB), whereas 456 (5.8%) were converted to on-pump (CONVERT). CONVERT patients were more severely ill. The observed mortality of CONVERT, CPB, and OPCAB was 9.9%, 3.0%, and 1.6%, respectively, and the observed-to-predicted ratio was 2.77, 1.20, and 0.74, respectively. CONVERT also had more morbidity than either OPCAB or CPB. Finally, a risk model was created to identify patients who might be at risk for conversion from off-pump to on-pump CABG. CONCLUSIONS: Patients who are intended for an off-pump strategy and then require conversion to on-pump have significantly higher operative mortality and morbidity than either completed OPCAB or CPB patients. In addition, the operative mortality and morbidity are far in excess of that predicted preoperatively. Based on these results, strong consideration should be given for a planned strategy of CPB for those patients with preoperative hemodynamic instability requiring a salvage CABG operation, left ventricular hypertrophy, or previous CABG.

Aged↗
PubMed2005

Is obesity a risk factor for mortality in coronary artery bypass surgery?

BACKGROUND: The published articles examining obesity and CABG surgery contain conflicting results about the role of body mass index (BMI) as a risk factor for in-hospital mortality. METHODS AND RESULTS: We studied 16 218 patients who underwent isolated CABG in the Providence Health System Cardiovascular Study Group database from 1997 to 2003. The effect of BMI on in-hospital mortality was assessed by logistic regression, with BMI group (underweight, normal, overweight, and 3 subgroups of obesity) as a categorical variable or transformations, including fractional polynomials, of BMI as a continuous variable. BMI was not a statistically significant risk factor for mortality in any of these assessments. However, using cumulative sum techniques, we found that the lowest risk-adjusted CABG in-hospital mortality was in the high-normal and that overweight BMI subgroup patients with lower or higher BMI had slightly increased mortality. CONCLUSIONS: Body size is not a significant risk factor for CABG mortality, but the lowest mortality is found in the high-normal and overweight subgroups compared with obese and underweight.

Aged↗
PubMed2005

Validation and refinement of mortality risk models for heart valve surgery.

BACKGROUND: The Northern New England Cardiovascular Disease Study Group (NNE) recently published risk models for hospital mortality after heart valve surgery. The Providence Health System Cardiovascular Study Group (PHS) has been collecting similar heart valve data for 8 years, providing an ideal opportunity to both validate the NNE risk models and attempt to produce an improved model, by using some different modeling techniques. METHODS: From 1997 to 2004, 3,324 patients aged 30 to 95 years underwent aortic valve replacement (AVR), and 1,596 underwent mitral valve replacement or repair (MVRR) at one of nine PHS medical centers. We used area under the receiver operating characteristic curve (c-index) to measure model discrimination, and Hosmer-Lemeshow statistic (H-L) to measure calibration. We modified the NNE models by ungrouping continuous variables, seeking optimal transformations of continuous variables, and imputing missing values by multiple regression. RESULTS: The prevalence and the lethality of risk factors were similar in PHS and NNE patients. The NNE models fit PHS patients well: c-index (95% confidence interval) = 0.75 (0.70 to 0.80) for AVR and 0.81 (0.76 to 0.86) for MVRR; H-L = 3.95 (p = 0.861) for AVR and 7.10 (p = 0.526) for MVRR. A single PHS model performed slightly better for both positions: c-index = 0.79 (0.75 to 0.83) for AVR and 0.84 (0.80 to 0.88) for MVRR; H-L = 2.75 (p = 0.949) for AVR and 12.21 (p = 0.142) for MVRR. CONCLUSIONS: The NNE models for aortic and mitral valve surgery were successfully validated using PHS patients. Using some different statistical approaches to modeling, we produced a new, unified model for both positions.

Adult↗
PubMed2005

Prognosis after aortic valve replacement with the Carpentier-Edwards pericardial valve: use of microsimulation.

BACKGROUND: The second-generation Carpentier-Edwards pericardial valve (Edwards Lifesciences LLC, Irvine, CA) is widely used for aortic valve replacement. However, knowledge on the long-term outcomes of patients after valve implantation is incomplete. We used microsimulation to calculate the long-term outcome of any given patient after aortic valve replacement with the Carpentier-Edwards pericardial valve. METHODS: A meta-analysis of 8 reports on aortic valve replacement with the Carpentier-Edwards pericardial valve (2,685 patients; 12,250 patient years) was used to estimate the hazards of valve-related events other than structural valvular deterioration. Structural valvular deterioration was described by age-dependent Weibull curves calculated from 18-year follow-up, premarket approval, Carpentier-Edwards pericardial primary data. These estimates provided the input data for the parameters of the microsimulation model, which was then used to calculate the outcomes of patients of different ages after valve implantation. The model estimates of survival were validated using two external data sets. RESULTS: The Weibull analysis estimated a median time to reoperation for structural valvular deterioration ranging from 18.1 years for a 55-year-old male to 23.2 years for a 75-year-old male. For a 65-year-old male, microsimulation calculated a life expectancy and event-free life expectancy of 10.8 and 9.1 years, respectively. The lifetime risk of at least one valve-related event was 38% and that of reoperation due to structural valvular deterioration 17%, respectively, for this patient. The model estimates of survival showed good agreement with external data. CONCLUSIONS: Microsimulation provides detailed insight into the long-term prognosis of patients after aortic valve replacement. The Carpentier-Edwards pericardial valve performs satisfactorily and offers a low lifetime risk of reoperation due to structural valvular deterioration, especially for elderly patients requiring aortic valve replacement.

Adult↗
PubMed2005

Additive vs. logistic risk models for cardiac surgery mortality.

OBJECTIVE: Logistic regression is most often used to produce a cardiac operative risk model. But the logistic equation requires a computer to solve. Thus, simple additive models have been derived from logistic models by adding the odds ratios or modified coefficients. However, this simplification has no statistical justification, and the additive scores do not equal the original logistic probabilities. METHODS: The EuroSCORE risk model is a very successful and widely used cardiac surgery risk model and it comes in both an additive and a full logistic version. We applied the EuroSCORE model to the 28,337 cardiac surgeries in the Providence Health System Cardiovascular Study Group database. The discrimination of the models was assessed by the c index. The comparison of the mortality predictions of the logistic and the additive model are mostly descriptive and graphical. RESULTS: Theoretical considerations would predict that the additive model greatly underestimates the risk for the higher risk patients, and clinical data confirm this fact. For the 23,463 (83%) cases with complete data, the predicted mortality was 8.3% by the logistic model and 5.4% by the additive model. The discrimination (c index) of the additive (0.794) and logistic (0.791) models was equally good. A modified additive score is proposed (the mean of the logistic predicted mortality for each original additive score) which could be provided as a look-up table along with the scoring sheet. CONCLUSIONS: The additive EuroSCORE gives excellent discrimination, as good as the logistic risk model, but it greatly underestimates the risk of high-risk patients, compared to the logistic. The logistic equation should be used to predicate the mortality when possible. If this is not feasible, a modified additive score could be employed at the bedside. But the logistic should always be used for comparison of providers and for research publications.

Cardiac Surgical Procedures↗
PubMed2004

Durability of pericardial versus porcine aortic valves.

OBJECTIVES: This study compares the long-term performance of the Carpentier-Edwards (CE) porcine bioprosthesis and the CE pericardial bioprosthesis for aortic valve replacement (AVR). BACKGROUND: With new bioprostheses on the horizon, there is renewed interest in how the long-term durability of current pericardial bioprostheses compares with the traditional porcine bioprosthesis. METHODS: We reviewed 518 AVR with CE porcine valves from 1974 to 1996 and 1,021 AVR with CE pericardial valves from 1991 to 2002. The age distribution and clinical profiles were similar for both groups. The total (mean) follow-up was 3,322 (6.4) years for porcine and 2,556 (2.5) years for pericardial. RESULTS: Long-term mortality was similar (p = 0.29) for porcine and pericardial, with 10-year survival rates of 34 +/- 2% and 38 +/- 6%, respectively. Ten-year freedom from major adverse cardiac events was also similar for both (respectively): thromboembolism (80 +/- 2% and 87 +/- 2%; p = 0.24); endocarditis (98 +/- 1% and 99 +/- 1%; p = 0.30). However, 10-year freedom from explant was lower for porcine (90 +/- 2%) than for pericardial (97 +/- 1%, p = 0.04). Reasons for explant for porcine were structural valve deterioration (SVD) (n = 25), endocarditis (n = 4), and periprosthetic leak (n = 2). The reasons for explant for pericardial were SVD (n = 4), endocarditis (n = 4) and periprosthetic leak (n = 1). CONCLUSIONS: The current CE pericardial valve offers better midterm durability than the traditional CE porcine valve. Its freedom from SVD and reoperation makes it our current bioprosthesis of choice for AVR in appropriately selected patients.

Adult↗
PubMed2004

The risks and benefits of reoperative aortic valve replacement.

BACKGROUND: Many patients are advised to have mechanical aortic valve replacement (AVR) because their expected longevity exceeds that of tissue prostheses. This strategy may avoid the risks of reoperation but exposes patients to the risks of long-term anticoagulation therapy. Which risk is greater? METHODS: We reviewed the records of 1213 consecutive, unselected AVR patients, 60% of whom had concomitant procedures, who were treated from 1994 through 2002. Of these patients, 887 were first-time AVR patients, and 326 underwent reoperation. Of the reoperation patients, 134 had previously undergone AVR (redo). We constructed a risk model from these 1213 cases to assess the factors that predicted mortality and to examine the extent to which reoperation affected outcome. RESULTS: Multiple logistic regression analysis indicated that factors of reoperation and redo operation did not predict mortality. In fact, the mortality rate was 4.1% for all first AVR operations and 3.1% for all reoperation AVR ( P =.891). Significant predicting factors (with odds ratios) were reoperative dialysis (6.03), preoperative shock (3.68), New York Heart Association class IV (2.20), female sex (1.76), age (1.61), and cardiopulmonary bypass time (1.26). CONCLUSIONS: In this series, the risk of reoperation AVR is comparable with the published risks of long-term warfarin sodium (Coumadin) administration after mechanical AVR. Any adult who requires AVR may be well advised to consider tissue prostheses.

Aged↗
PubMed2004

Mitral valve operations through standard and smaller incisions.

OBJECTIVE: Evaluate the operative results of mitral valve repair (MVV) and mitral valve replacement (MVR) performed through standard and smaller incisions. METHODS: From January 1997 through December 2002, 821 consecutive patients underwent mitral valve operation. Of these procedures, 475 were MVV and 346 were MVR. A logistic regression model was developed to identify the risk factors for early mortality and to evaluate the effect of replacement versus repair and standard versus small incision. RESULTS: Replacement patients were older, more likely New York Heart Association (NYHA) class III or IV, more likely female, and had more frequent previous median sternotomy and stroke (all P <.05). The mitral diagnoses in the 2 groups were markedly different. Prolapse and ischemia dominated the repairs, whereas calcific and rheumatic diagnoses required replacement. There were 667 concomitant procedures performed on these patients, most commonly coronary artery bypass graft (229), aortic valve replacement (170), maze (79), and tricuspid valve (TV) repair/replacement (73). Thirty-three patients (4.0%) died in the postoperative period, 2.3% after repair and 6.4% after replacement ( P <.01). Endocarditis (4/17), calcific disease (7/73), and ischemic disease (9/121) accounted for 26% of patients and 60% of deaths. Multivariate regression analysis identified NYHA class, emergent status, concomitant TV operation, and history of renal failure, but not repair versus replacement, as independent risk factors predicting mortality. We estimated that 356 of the 821 patients (43%) were candidates for small-incision operations, the others were excluded by the need for concomitant procedure or other cause. A total of 205/356 (57%) actually underwent small-incision operations, all with central cannulation and standard techniques. From 1997-1999, 32% of eligible patients were so treated, but from 2000-2002, with increasing surgeon experience, this percentage rose significantly to 71% ( P <.01). Eligible patients who underwent small-incision operation were younger and had lower NYHA classifications, lower preoperative creatinine, and shorter length of stay (all P <.01) than those who had standard incisions. Cross-clamp time, perfusion time, and mortality rate were not significantly different. CONCLUSIONS: The mortality rate for MV operations is concentrated among a few diagnoses. In some patients surgery may be approached safely through smaller incisions without introducing new elements of operative risk.

Aged↗
PubMed2004

Sternal preservation: a better way to treat most sternal wound complications after cardiac surgery.

BACKGROUND: Postcardiotomy sternal wound complications remain challenging. The prevailing approach for deep sternal wound infection of debridement and flap coverage without osseous closure makes subsequent reoperation difficult. METHODS: An analysis of all patients undergoing cardiac surgery at a single institution between 1986 and 2001 was conducted. Prospective data collection and chart review were used to compare different treatment strategies for sternal complications. RESULTS: Of 5337 patients, 122 had sternal wound complications (2.2%) comprising 15 (0.3%) uninfected dehiscences (El Oakley class 1), 45 (0.8%) superficial infections (El Oakley class 2A), and 62 (1.1%) deep sternal wound infections (El Oakley class 2B). Thirty-two patients with deep sternal infection were treated by debridement, rewiring, and delayed primary closure. There were initial treatment failures in 6 patients (18.8%) and ultimate failures in 2 patients (6.3%), both of whom died. One of these patients had previously received external beam radiation after a radical mastectomy for breast cancer. Median length of stay was 32 days and median time to wound healing was 85 days. Twenty-five patients were managed by muscle flap coverage without sternal reclosure. There were 6 initial treatment failures (24%) but no ultimate failures or deaths (p = NS). Median length of stay was 31 days and median infection time was 161 days. CONCLUSIONS: In patients with postcardiotomy deep sternal wound infection without previous chest radiation, debridement, rewiring, and delayed skin closure is effective. It offers a shorter healing time and probably makes late cardiac reoperation safer. We propose an algorithm for the management of poststernotomy complications.

Algorithms↗
PubMed2004

Cardiac surgery risk models: a position article.

Differences in medical outcomes may result from disease severity, treatment effectiveness, or chance. Because most outcome studies are observational rather than randomized, risk adjustment is necessary to account for case mix. This has usually been accomplished through the use of standard logistic regression models, although Bayesian models, hierarchical linear models, and machine-learning techniques such as neural networks have also been used. Many factors are essential to insuring the accuracy and usefulness of such models, including selection of an appropriate clinical database, inclusion of critical core variables, precise definitions for predictor variables and endpoints, proper model development, validation, and audit. Risk models may be used to assess the impact of specific predictors on outcome, to aid in patient counseling and treatment selection, to profile provider quality, and to serve as the basis of continuous quality improvement activities.

Bayes Theorem↗
PubMed2004

Outcomes after usage of a quality initiative program for off-pump coronary artery bypass surgery: a comparison with on-pump surgery.

BACKGROUND: Off-pump coronary artery bypass (OPCAB) may be associated with improved outcomes when compared with on-pump coronary artery bypass. This study evaluates the use of a system for access and stabilization (SAS) with a coronary stabilizer as well as a clinical effectiveness quality initiative (CEQI) process regarding outcomes. This included the development of an expanded heart care team as well as standardization and refinement of perioperative care at The Lankenau Hospital (TLH). Our aim was to evaluate morbidity and mortality of on-pump coronary artery bypass grafting (CABG) compared with OPCAB surgery using SAS in addition to a CEQI initiative. METHODS: A retrospective consecutive cohort study using the Society of Thoracic Surgery (STS) National Database was conducted. Three cohorts were analyzed: pre-SAS (December 1, 1999-August 31, 2000); use of SAS only (September 1, 2000-April 30, 2001), and the use of SAS + CEQI process (May 1, 2001-September 30, 2002). Morbidity and mortality for all on-pump CABG procedures performed over the time period of December 1, 1999-September 30, 2002 were compared with the SAS and SAS + CEQI groups only. RESULTS: One-thousand two-hundred sixty-seven procedures were performed; 405 on-pump CABGs, 90 OPCABs pre-SAS, and 772 OPCABs with SAS, of which 552 were in the SAS + CEQI group. Statistically mortality was significantly lower in the SAS + CEQI vs the on-pump group (0.7% vs 3.0%, p < 0.01). The percentage of patients with prolonged ventilation was significantly lower statistically in the SAS + CEQI vs the on-pump group (4.2% vs 9.7%, p < 0.01). Statistically the length of stay was significantly lower in both SAS groups compared with the on-pump group (p < 0.01). CONCLUSIONS: OPCAB surgery using SAS in conjunction with a CEQI initiative improves outcomes for patients compared with on-pump CABG surgery.

Cohort Studies↗
PubMed2004

The Silzone effect: how to reconcile contradictory reports?

OBJECTIVE: To attempt to reconcile reports containing contradictory findings with the St. Jude Medical Silzone heart valve. METHODS: Major leak and thromboembolism data were extracted from available Silzone valve studies. Linearized rates were used to summarize and compare the events rates among the studies. RESULTS: The Artificial Valve Endocarditis Reduction Trial (AVERT) study reported significant higher rate of major leak and the Cardiff Embolic Risk Factor Study (CERFS) reported significant higher rate of thromboembolism with Silzone compared to non-Silzone valves. But, current updates of these studies show a diminution of these differences. Three other comparative studies reported no difference between Silzone and non-Silzone valves, and three single arm studies reported acceptable results with Silzone valves. CONCLUSION: The contradictory findings could be partly due to clinical and technical reasons. No new events have been reported since the original AVERT (major leak) and CERFS (mitral thromboembolism) publications.

Endocarditis↗