Molecular and pathological studies in the posterior interosseous nerve of diabetic and non-diabetic patients with carpal tunnel syndrome.

AIMS/HYPOTHESIS: We sought to establish the molecular and pathological changes predisposing diabetic and non-diabetic patients to the development of carpal tunnel syndrome (CTS). METHODS: The posterior interosseous nerve (PIN) was biopsied in 25 diabetic and 19 non-diabetic patients undergoing carpal tunnel decompression for CTS. Detailed morphometric and immunohistological analyses were performed in the nerve biopsy. RESULTS: In diabetic patients median nerve distal motor latency was prolonged (p < 0.05 vs non-diabetic patients), PIN myelinated fibre density (p < 0.05), fibre area (p < 0.0001) and axon area (p < 0.0001) were reduced, the percentage of unassociated Schwann cell profiles (p < 0.0001) and unmyelinated axon density (p < 0.0001) were increased and the axon diameter was reduced (p < 0.0001). Endoneurial capillary basement membrane area was increased (p < 0.0001) in diabetic patients, but endothelial cell number was increased (p < 0.01) and luminal area was reduced (p < 0.05) in non-diabetic patients with CTS. There was no difference in the expression of hypoxia-inducible factor 1α between diabetic and non-diabetic patients with CTS. However, the expression of vascular endothelial growth factor A (VEGF) (p < 0.05) and its receptors VEGFR-1 (p < 0.01) and VEGFR-2 (p < 0.05) was significantly increased in diabetic patients, particularly those with type 1 diabetes, and related to the severity of nerve fibre pathology. CONCLUSIONS/INTERPRETATION: This study demonstrates increased nerve fibre and microvascular pathology in relation to enhanced expression of VEGF and its receptors in a non-compressed nerve in diabetic compared with non-diabetic patients with CTS. It therefore provides a potential molecular and pathological basis for the predisposition of diabetic patients to the development of CTS.

Use of the sheathless guide catheter during routine transradial percutaneous coronary intervention: a feasibility study.

OBJECTIVE: The aim of this study is to investigate the feasibility of using a 6.5 Fr sheathless guide catheter as a default system in transradial (TRA) percutaneous coronary intervention (PCI). BACKGROUND: TRA PCI has been shown to reduce mortality rates through a reduction in access site related bleeding complications compared with procedures performed though a femoral approach. Complications associated with the TRA route increase with the size of sheath used. These complications may be reduced by the use of a sheathless guide catheter system (Asahi Intecc, Japan) that is 1-2 Fr sizes smaller in diameter than the corresponding introducer sheath. METHODS: We performed PCI in 100 consecutive cases using 6.5 Fr sheathless guides to determine the procedural success, rates of symptomatic radial spasm and radial occlusion. RESULTS: Procedural success using the 6.5 Fr sheathless guide catheter system was 100% with no cases requiring conversion to a conventional guide and catheter system. There were no procedural complications recorded associated with the use of the catheter. Adjunctive devices used in this cohort included IVUS, stent delivery catheters, distal protection devices, and simple thrombectomy catheters. The rate of radial spasm was 5% and the rate of radial occlusion at 2 months was 2%. CONCLUSION: Use of the 6.5 Fr sheathless guide catheter system, which has an outer diameter <5 Fr sheath, as the default system in routine PCI is feasible with a high rate of procedural success via the radial artery.

Atrial fibrillation is under-recognized in chronic heart failure: insights from a heart failure cohort treated with cardiac resynchronization therapy.

AIMS: Atrial fibrillation (AF) is the most common sustained arrhythmia in patients with chronic heart failure (CHF). Under-detection of asymptomatic paroxysmal AF (PAF) underestimates the true burden of AF in patients with CHF. We retrospectively studied the prevalence of asymptomatic PAF in 162 CHF patients through analysis of cardiac resynchronization therapy (CRT) device downloads to determine whether these episodes are associated with adverse outcomes. METHODS AND RESULTS: An episode of AF was defined by mode switching on CRT devices with an atrial rate >200 for at least 30 s. Of the 101 patients thought to be persistently in sinus rhythm (SR), 27% were found to have significant paroxysms of AF, with the cumulative percentage of time in the 'mode-switch mode' (i.e. the AF burden) of 1.6 +/- 0.9%. Mortality was 19.2% in patients with newly identified PAF with hospitalization and thrombo-embolism rates of 42.3 and 2.1%, respectively, compared with mortality of 10.4% with hospitalization and thrombo-embolism rates of 41.8 and 1.9%, respectively, in patients persistently in SR (P= NS). CONCLUSION: Analysis of data from CRT devices in a population of CHF patients with severe left ventricular dysfunction shows that a significant proportion of those perceived to be persistently in SR have undiagnosed paroxysms of AF but with relatively low burden. These episodes appear to be associated with a trend towards increased mortality but no effects on hospitalization or thrombo-embolism rates.