Diabetic autonomic neuropathy: conventional cardiovascular laboratory testing and new developments

Cardiovascular reflex tests remain the investigational cornerstone for the assessment of patients in the clinical autonomic laboratory. Three cardiovagal tests have been found suitable for testing: the instantaneous heart rate responses induced by deep breathing, Valsalva's manoeuvre and standing up. Suitable laboratory indices of adrenergic function include continuous monitoring of blood pressure responses induced by Valsalva's manoeuvre and standing up, which is now possible through tracking of beat-to-beat blood pressure changes at the finger. Spectral analysis of heart rate and blood pressure and pulse wave analysis for stroke volume changes are promising approaches to evaluate abnormalities in arterial baroreflex regulatory mechanisms in diabetic patient

Long-term effects of carotid sinus denervation on arterial blood pressure in humans.

Item does not contain fulltextBACKGROUND: After experimental carotid sinus denervation in animals, blood pressure (BP) level and variability increase markedly but normalize to preoperative levels within 10 to 14 days. We investigated the course of arterial BP level and variability after bilateral denervation of the carotid sinus baroreceptors in humans. METHODS AND RESULTS: We studied 4 women (age 41 to 63 years) who were referred for evaluation of arterial baroreflex function because of clinical suspicion of carotid sinus denervation attributable to bilateral carotid body tumor resection. The course of BP level and variability was assessed from repeated office and 24-hour ambulatory measurements (Spacelabs/Portapres) during 1 to 10 years of (retrospective) follow-up. Rapid cardiovascular reflex adjustments to active standing and Valsalva's maneuver were assessed. Office BP level increased from 132/86 mm Hg (range, 118 to 148/80 to 92 mm Hg) before bilateral surgery to 160/105 mm Hg (range, 143 to 194/90 to 116 mm Hg) 1 to 10 years after surgery. During continuous 24-hour noninvasive BP recording (Portapres), a marked BP variability was apparent in all 4 patients. Initial symptomatic hypotension on change to the upright posture and abnormal responses to Valsalva's maneuver were observed. CONCLUSIONS: Acute carotid sinus denervation, as a result of bilateral carotid body tumor resection, has a long-term effect on the level, variability, and rapid reflex control of arterial BP. Therefore, in contrast to earlier experimental observations, the compensatory ability of the baroreceptor areas outside the carotid sinus seems to be of limited importance in the regulation of BP in humans

The association of body mass index with safety and effectiveness of first-line carboplatin-based chemotherapy in patients with metastatic non-small cell lung cancer

Introduction: Carboplatin is an anticancer drug used for treatment of various types of cancer including non-small cell lung cancer (NSCLC). Dosing is based on estimated glomerular filtration rate (GFR) using the Cockcroft-Gault formula. In overweight patients, the GFR is more likely overestimated, resulting in a potentially overdose of carboplatin affecting treatment response. This study investigated the association of body mass index (BMI) on overall survival (OS) and progression-free survival (PFS) in stage-IV NSCLC patients treated with first-line carboplatin-based chemotherapy. Secondary safety endpoints were thrombocytopenia and toxicity-related hospitalizations. Materials and methods: This was a retrospective multicenter cohort study. Patients were categorized according to BMI<25.0 kg/m2 (normal weight and reference), 25.0-29.9 kg/m2 (overweight) or ≥30.0 kg/m2 (obese). For survival analyses adjusted hazard ratios [aHR] were calculated using multivariate Cox regression analysis. Secondary outcomes were analyzed using multivariate logistic regression providing adjusted odd ratios [aOR]. Results: Overweight patients (n=174) had a significantly better OS (aHR=0.72, 95%-CI:0.59-0.89) and PFS (aHR=0.74, 95%-CI:0.61-0.90) compared to normal weight patients (n=268). OS nor PFS were different in obese (n=51) compared to normal weight patients. However, obesity was associated with significantly higher incidences of thrombocytopenia grade ≥3 (aOR=3.47, 95%-CI:1.75-6.90). Conclusion: This study shows a significantly longer survival for overweight compared to normal weight patients. Obese patients have an increased risk for grade ≥3 thrombocytopenia without a difference in survival following carboplatin-based chemotherapy. The implications for clinical practice are to use the Cockcroft-Gault formula with caution in patients with BMI≥30.0 kg/m2, and to verify calculated dosing of carboplatin for appropriateness