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Biomedical subjects

G L Grunkemeier

Publications and source records attributed to G L Grunkemeier.

At least 19 recordsLinked to original sources
PubMed1992

Strut fracture with Björk-Shiley 70 degrees convexo-concave valve. An international multi-institutional follow-up study.

Between 1980 and 1983, 831 Björk-Shiley 70 degrees convexo-concave prosthetic heart valves were implanted at five institutions in Sweden, Germany. The Netherlands, and Canada. As of January 1991, there were 34 outlet strut fractures occurring from 0.2 to 10.1 years (median = 4.6 years) after implantation. In addition, there were 28 sudden, unexplained deaths. The mortality after strut fracture was 84%. The mortality after emergency valve replacement for strut fracture was 50%. The 10-year actuarial fracture rate (standard error) was 10.5 (2.4)% for large (29-33 mm) valves vs. 3.3 (1.2)% for 21-27 mm valves (P less than 0.001). Within valve size groups, fracture rates for aortic and mitral valves were similar. Cox regression analysis found only valve size to be significantly associated with strut fracture. There is a further subgrouping of the valves according to the manufacturer: group I are the earlier large 29-33 mm) valves; group II are the later large valves; group III are the small size (21-27 mm) valves. The risk of strut fracture was highest in group I (12.3% at 10 years) with an approximatively constant hazard (1.4% per year). A comparison was made with a statistical model incorporating all cases reported to the manufacturer. This model estimates fracture rates approximately 63%-73% of those found in the present study. These findings lead us to recommend that group I patients should be considered for elective reoperation on an individual basis, giving careful attention to risk factors and contraindications.

Adolescent↗
PubMed1992

Alternatives to randomization in surgical studies.

The purpose of randomization is to provide unbiased estimates of treatment effects and valid probability statements for hypothesis tests in comparative studies. Difficulties with randomized allocation of patients in surgical studies include: patient selection--due to protocol limitations, possible changes in referral patterns, the need for patient consent, and physician co-operation; disruption of the patient-physician relationship; static protocol not responsive to changes as surgical skill evolves and experience regarding patient selection is acquired; the larger number of patients required causes a longer study and more patients receiving what may be a worse therapy. Moreover, for evaluating a new heart valve, the primary purpose should be estimation rather than comparison with a current device. This can be accomplished faster, in a more generalizable way and with more concern for patient care by using non-randomized comparison groups.

Ethics, Medical↗
PubMed1992

Risk of recoarctation in neonates and infants after repair with patch aortoplasty, subclavian flap, and the combined resection-flap procedure.

Between September 1980 and August 1988, 47 patients younger than 12 months (27 neonates and 20 infants) underwent repair of aortic coarctation. Three surgical techniques were used: patch aortoplasty (group A: 5 neonates and 3 infants, mean age 4.5 months), subclavian flap (group B: 11 neonates and 8 infants, mean age 3.1 months), and the combined resection-flap procedure (group C: 11 neonates and 9 infants, mean age 2.7 months). There were 8 early deaths (3 in group A, 3 in group B, and 2 in group C) and 2 late deaths (both in group B), all of which occurred in patients with complex coexisting anomalies. Follow-up included 37 patients (5 in group A, 14 in group B, and 18 in group C) and ranged from 28 to 108 months (mean 68.0, 60.8, and 51.7 months, respectively). Residual arm-leg pressure gradients greater than 10 mm Hg were detected in 4 of 5 patients in group A, 11 of 14 patients in group B, and 1 of 18 patients in group C (p less than 0.005). There were no reoperations in any infant operated on after 1 month of age in any group (0% risk). However, 4 patients who underwent repair during their neonatal period, with recurrent gradients greater than 20 mm Hg, have required reoperation: in group A, 1 of 5 patients (20% risk) (1 of 2 neonates or 50% risk); in group B, 3 of 14 patients (21% risk) (3 of 9 neonates or 33% risk); and none in group C (0% risk in infants and neonates) (p less than 0.001). In summary, residual gradients and risk of recoarctation are significantly higher when a patch or a subclavian flap had been used for repair. The combined resection-flap procedure (an end-to-end anastomosis enlarged with a subclavian flap) is more effective in avoiding gradients and preventing recoarctation, especially in neonates.

Anastomosis, Surgical↗
PubMed1990

Sternotomy infection: poor prediction by acute phase response and delayed hypersensitivity.

Two hundred twenty-one consecutive adult cardiac surgical patients were examined prospectively for nutritional protein state, acute phase protein response, and delayed hypersensitivity reaction in an attempt to identify patients at high risk for the development of sternal wound infection, which occurred in 6 patients (2.7%). There was no significant correlation between preoperative nutritional protein concentrations (retinol-binding protein, prealbumin, and transferrin) and acute phase protein levels (C-reactive protein, alpha 1-acid glycoprotein, and complements B and C3), nor a statistically significant relationship between nutritional state or acute phase protein response and the development of sternal infection. Preoperative complement C3 levels were elevated, however, in 80.0% of those in whom sternal infections developed compared with 30.6% of those with well-healed wounds. Similarly, postoperative concentrations of alpha 1-acid glycoprotein were elevated in 80.0% of those in whom sternal infections developed compared with 28.6% of those with well-healed wounds. There was no correlation between delayed hypersensitivity and the risk of sternal infection, nor between preoperative nutritional protein and acute phase protein values. Seventy-three percent of patients were anergic on postoperative day 2. Stepwise logistic regression showed that age, body weight, preoperative intensive care unit stay, repeat median sternotomy, internal mammary artery grafting, postoperative hemorrhage, and postoperative cardiac arrest correlated with the development of sternal infection, whereas transfusion requirement, reexploration for bleeding, and the operation performed did not. We conclude that routine delayed hypersensitivity testing is of no value in predicting high-risk cardiac surgical patients when the anergy battery is placed on the preoperative day. Although statistically insignificant, possibly due to the small number of patients in whom sternal infection developed in this study (type II error), a larger study might find preoperative complement C3 and post-operative alpha 1-acid glycoprotein levels to be predictive of patients at risk for the development of sternal wound infection. The final logistic model for the predicted risk 2%) of sternal wound infection is: PREDSWC = exp(EQ)/1 + exp(EQ) where EQ = (0.38 x age) + (0.24 x weight) + (5.42 x preop ICU) + (4.39 x redo) + (7.14 x IMA) + (4.49 x hemorrhage) + (8.81 x arrest) - 62.72, and where preop ICU, redo, hemorrhage, and arrest are defined as yes (1) or no (0), IMA-is defined as 0, 1, or 2, age is in years, and weight is in kilograms.

Acute-Phase Proteins↗
PubMed1990

Artificial heart valves.

This overview of heart valve prostheses is based on a current review of clinical reports and focuses on the major complications that characterize long-term valve performance: thromboembolism, thrombosis, anti-coagulant-related bleeding, and structural failure.

Bioprosthesis↗
PubMed1990

Tricuspid valve operations in 530 patients. Twenty-five-year assessment of early and late phase events.

From Jan. 1, 1961, through Dec. 31, 1987, 530 patients underwent an intracardiac operation that included a tricuspid valve procedure. The tricuspid valve was repaired in 351 patients (66%) and replaced in 179 (34%). Mean age was 56.9 years. Risk factors associated with tricuspid valve replacement included tricuspid stenosis (p = 0.02), jugular venous distention (p = 0.04), previous operation (p = 0.05), and angiographic severity of tricuspid valve incompetence (p less than 0.001). There were 78 hospital deaths (15%). Risk factors for hospital death included previous operation (p = 0.03), male gender (p = 0.03), hepatomegaly (p = 0.03), De Vega or Carpentier annuloplasty (repair group only), (p = 0.01), and older age at operation (p = 0.06). Ninety-eight percent of the patients were followed up. There were 185 late deaths (41%). The actuarial survival rate was 20% at 180 months. Risk factors for late death included male gender (p = 0.03), hepatomegaly (p = 0.04), and lack of postoperative warfarin therapy (p less than 0.001). Actuarial freedom from reoperation was 25.5% at 180 months. There was no difference in reoperation rates (p = 0.10) or survival (p = 0.42) whether the tricuspid valve had been repaired or replaced. We conclude that the requirement for surgical treatment of tricuspid valve insufficiency in patients with multivalvular disease constitutes a high risk group for cardiac surgery. Preoperative variables may predict the result of tricuspid valve replacement. Tricuspid valve replacement may be performed with the expectation of a low risk of valve-related events.

Aged↗
PubMed1989

Comparison of coronary artery bypass grafting and percutaneous transluminal coronary angioplasty as initial treatment strategies.

Early and late results of primary nonemergency coronary artery bypass grafting in 1,000 consecutive patients and primary nonemergency percutaneous transluminal coronary angioplasty performed concurrently in 389 patients were retrospectively compared. The coronary bypass population was significantly older and more symptomatic and had more prior myocardial infarctions, more left main and multiple-vessel coronary artery disease, and poorer ventricular function. Hospital mortality rates for coronary bypass grafting and angioplasty were 0.4% and 0.5%, respectively, and infarction rates were 1.7% and 5.1%, respectively (p less than 0.01). Including hospital events for the coronary bypass and angioplasty populations, actuarial survival at 5 years was 92.3% versus 96.3% (p = 0.04), freedom from myocardial infarction was 94.6% versus 88.1% (p less than 0.001), freedom from subsequent angioplasty was 99.5% versus 75.2% (p less than 0.001), freedom from subsequent coronary bypass grafting was 98.8% versus 84.9% (p less than 0.001), and freedom from all morbidity and mortality was 87.1% versus 66.0% (p less than 0.001), respectively. By Cox regression analysis for all 1,389 patients, only diminished ejection fraction and advanced age predicted poor long-term survival (p less than 0.001). The only significant predictor of nonfatal late events was having had coronary angioplasty.

Angioplasty, Balloon↗
PubMed1988

Outlet strut fracture of the Björk-Shiley 60 degrees Convexo-Concave valve: current information and recommendations for patient care.

Mechanical failure of artificial heart valves can be a catastrophic event. The problem of outlet strut fracture of the Björk-Shiley 60 degrees Convexo-Concave tilting disc prosthesis has received much attention in the medical literature and generated both concern and confusion among patients and physicians. Analysis of current data from the manufacturer, as well as a review of the medical literature, suggests that the overall risk of outlet strut fracture is low and that elective explantation of a well functioning Björk-Shiley 60 degrees Convexo-Concave valve prosthesis is not warranted. Diagnostic features of outlet strut fracture can be seen with overpenetrated chest X-ray films so that diagnosis can be established promptly. Early operation to replace the fractured prosthesis is essential for patient survival.

Aortic Valve↗
PubMed1988

Tissue and mechanical valves: mutually advantageous interplay.

This report is concerned with the dynamic interplay between glutaraldehyde preserved tissue valves (bioprostheses) and mechanical valves. These two classes of valve replacement devices are not competitive, but provide some nonoverlapping characteristic advantages and disadvantages. By proper selection, it may be possible to tailor the kind of device used for a particular patient, thus improving the overall results of bioprosthetic and mechanical valve replacement. Careful selection of patients according to age and the safety of anticoagulation should achieve a series of patients with mechanical and bioprosthetic valves that would be superior to a series in which all patients received a single device. Thus, these devices should be viewed as complimentary rather than competitive since the value of properly matching a prosthesis to the patient will be reflected in improved overall results with each class of prosthesis.

Age Factors↗
PubMed1988

Twenty-five year experience with Starr-Edwards heart valves: follow-up methods and results.

A prospective data registry and follow-up service has been in use for cardiac surgery patients at the St Vincent Hospital Heart Institute, Portland, Oregon, since 1960. It presently contains information on more than 4,000 heart valve operations. The physical system has evolved from a manually updated binder of flowsheets to an integrated multicomputer database. The caged-ball valves used as the predominant replacement device have themselves performed successfully, permitting a remarkable 25-year review. The conclusions from a current review of the valves, which have just entered their third decade of use, remain the same as the conclusions from an earlier review of the same series, performed 10 years ago when the valves had just entered their second decade of use.

Aortic Valve↗
PubMed1988

Low risk of thrombosis and serious embolic events despite low-intensity anticoagulation. Experience with 1,004 Medtronic Hall valves.

One thousand four Medtronic Hall valves (601 mitral, 398 aortic, and five tricuspid) were implanted in 847 patients between December 1979 and June 1987. Total experience at the end of June 1987 was 2,640 patient-years of follow-up. Prothrombin time ratios were reviewed for all patients (16,866 observations), and these ratios were found to be therapeutically low (median international normalized ratio, 2.6) and highly variable (lower 10th percentile, 1.6; upper 10th percentile, 3.9). During the follow-up period, there were no valvular thromboses; the 95% confidence limit for the risk of thrombosis (0.14 per 100 patient-years) is below that reported for other mechanical prostheses. Sixty percent of all thromboembolic events left no residual deficit, and 75% of all bleeding events did not require treatment. Only 11% of thromboembolic events and 7% of bleeding events were fatal. The linearized rate of fatal bleeding was 0.2% per year, and the linearized rate of moderate to severe bleeding was 0.5% per year. Five-year actuarial embolic-free rates were 92%, 84%, and 83% for aortic, mitral, and double valves, respectively. The low risk of valvular thrombosis and of serious thromboembolic events in the Medtronic Hall valve, regardless of the range and variability of anticoagulation, offers greater patient safety than other mechanical prostheses, provides a credible alternative to bioprostheses, and may be particularly relevant to third-world populations.

Actuarial Analysis↗
PubMed1987

A tri-institutional comparison of tissue and mechanical values using a patient-oriented definition of "treatment failure".

Selection of valve type for predominant usage is obscured by limiting the analysis to prosthesis-related rather than patient-oriented failure modes. In this report, "treatment failure" is defined as a valve-related death or permanent patient disability; successful reoperations are excluded, and emboli with permanent residua are included. Results with the Starr-Edwards Silastic ball valve (Oregon) and the Hancock (Stanford) and Carpentier-Edwards (Vancouver) porcine valves are compared using this new definition of treatment failure. Evaluated according to structural failure, the mechanical valve is superior to the tissue valve, and using the Stanford definition of valve failure, it becomes so between 5 and 10 years. Using treatment failure, tissue valves are superior at 5 years; at 10 years in the aortic position, the results are comparable; and in the mitral position at 8 to 10 years, tissue valves show a continued but small advantage.

Aortic Valve↗
PubMed1986

Late right ventricular reconstruction following valvotomy in pulmonary atresia with intact ventricular septum.

Experience over two decades in the surgical management of pulmonary atresia with intact ventricular septum demonstrates that eventual right ventricular (RV) reconstruction is possible in the majority of patients surviving valvotomy in infancy. Ten of 17 operative survivors of early valvotomy have eventually received a patch graft to the RV outflow tract, with no reoperative deaths (mean follow-up, 7.4 years). RV systolic pressures, suprasystemic prior to reoperation, are near normal after outflow patch reconstruction. Serial cineangiograms show evidence of RV growth by measurement of tricuspid annulus diameter (TAD), and demonstrate a rate of growth [d(TAD)/d(body length)] greater than a normal rate derived from autopsy data. The mean TAD growth rate is significantly greater than that of patients with less favorable ventricle types treated with a systemic-pulmonary shunt alone. Measurement of TAD is a useful method for following RV growth, and may aid in selecting patients for RV reconstruction.

Adolescent↗