Cardiovascular risk assessment of the diabetic patient undergoing major noncardiac surgery

Diabetic patients have increased perioperative cardiac risk in heart-type fatty acid-binding protein-based assessment

OBJECTIVE

To test the potential role of heart-type fatty acid-binding protein (H-FABP) in detecting increased perioperative cardiac risk in comparison with cardiac troponin I (cTnI) in the early postoperative period.

SUBJECTS AND METHODS

Sixty-seven patients who had clinical risk factors and underwent elective intermediate - or high-risk noncardiac surgery were included in this study. Serum specimens were analyzed for H-FABP and cTnI levels before and at 8 h after surgery. None of the patients had chest pain; 27 had a history of ischemic heart disease, 3 of heart failure, 5 of cerebrovascular diseases, 40 of diabetes and 46 of hypertension.

RESULTS

The mean duration of the operations was 2.33 ± 1.27 h (range 1-6). In the postoperative period, 27 (40.3%) patients had increased H-FABP levels (≥7.5 ng/ml); the median preoperative serum H-FABP level was 0.13 ng/ml (<0.1-5.9) and the median postoperative H-FABP level was 6.86 ng/ml (<0.1-13.7). Only 1 (1.5%) patient had cTnI >0.1 µg/l during the postoperative period. Correlation analysis revealed that the presence of diabetes was associated with an increased H-FABP level (r = 0.30, p = 0.01). Of the 27 patients with H-FABP ≥7.5 ng/ml, 21 (87%) had diabetes. There was no significant correlation with other clinical risk factors, type or duration of surgery.

CONCLUSION

The H-FABP levels significantly increased in the postoperative period. Most patients with increased postoperative H-FABP levels were diabetic. High H-FABP levels could alert clinicians to increased perioperative cardiovascular risk and could prevent underdiagnosis, especially in diabetic patients.

Effect of isoflurane on myocardial energetic and oxidative stress in cardiac muscle from Zucker diabetic fatty rat

The effect of inhalational anesthetics on myocardial contraction and energetics in type 2 diabetes mellitus is unknown. We investigated the effect of isoflurane (ISO) on force and intracellular Ca(2+) transient (iCa), myocardial oxygen consumption (MVo(2)), and energetics/redox behavior in trabecular muscles from Zucker diabetic fatty (ZDF) rats. At baseline, force and corresponding iCa were lower in ZDF trabeculae than in controls. ISO decreased force in both groups in a dose-dependent manner. ISO did not affect iCa amplitude in controls, but ISO > 1.5% significantly reduced iCa amplitude in ZDF trabeculae. ISO-induced force depression fully recovered as a result of increased iCa when external Ca(2+) was raised in controls. However, both force and iCa remained low in ZDF muscle at elevated external Ca(2+). In controls, force, iCa, and MVo(2) increased when stimulation frequency was increased from 0.5 to 1.5 Hz. ZDF muscles, however, exhibited blunted responses in force and iCa and decreased MVo(2). Oxidative stress levels were unchanged in control muscles but increased significantly in ZDF muscles after exposure to ISO. Finally, the depressive effect of ISO was prevented by 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (Tempol) in ZDF muscles. These findings suggest that ISO dose-dependently attenuates force in control and ZDF muscles with differential effect on iCa. The mechanism of force depression by ISO in controls is mainly decreased myofilament Ca(2+) sensitivity, whereas in ZDF muscles the ISO-induced decrease in contraction is due to worsening oxidative stress, which inhibits iCa and force development.

Risk factors for the development of serious medical complications after resection of meningiomas. Clinical article

OBJECT

While the surgical and neurological risks of meningioma surgery have been reported, much less effort has been devoted to studying the rates of serious medical complications following such a procedure. The authors performed a review of 834 patients who underwent craniotomy for meningioma at their institution and analyzed the rate of major cardiac, pulmonary, renal, and hepatic complications.

METHODS

The authors identified all patients between 1993 and 2007 who underwent craniotomy for meningioma. Clinical information was reconstructed using patient medical records, medication records, radiological data, and pathological specimens from both the author institution and outside medical facilities. Stepwise multivariate logistic regression analysis was performed to test the association between the dependent variable (rate of medical complications) and all covariates with a p < 0.2 on univariate testing.

RESULTS

Fifty-seven patients (6.8%) experienced 61 serious medical complications following surgery for meningioma. Four patients died of medical complications. The most common complication was pneumonia, followed by renal dysfunction, arrhythmia, and deep venous thrombosis and/or pulmonary embolus. The development of a new or worsened neurological deficit (p < 0.00001), an age > 65 years (p < 0.03), hypertension (p < 0.02), and being on > 2 cardiac medications prior to surgery (p < 0.004) all demonstrated significantly increased rates of medical complications on univariate analysis. On multivariate analysis, only a new or worsened neurological deficit remained a significant risk factor for the occurrence of serious medical complications (p < 0.00001).

CONCLUSIONS

Overall, the authors found that the rate of clinically detected serious medical complications is relatively low in this population (6.8%), given the duration and complexity of the meningioma operations, and is strongly linked to the subsequent development of significant medical complications. This information may be useful to surgeons in discussing the morbidity of surgery during the informed consent process.