Biomedical subjects

Markus Exner

Publications and source records attributed to Markus Exner.

75 records · Page 5Linked to original sources

PubMed2002

Fibrinogen predicts restenosis after endovascular treatment of the iliac arteries.

OBJECTIVE: Fibrinogen is an acute phase protein as well as a component of the coagulation cascade. Vascular inflammation and disturbed coagulation are suggested to cause restenosis after percutaneous transluminal angioplasty (PTA). We investigated the prognostic impact of fibrinogen on restenosis after endovascular treatment of iliac artery occlusive disease. METHODS: In a prospective cohort study 137 consecutive patients after iliac artery PTA (n = 74) and PTA plus selective stent implantation (n = 63) were included, 109 patients after lower limb angiography served as a control group. Patients were followed for 6 months with oscillography, ankle brachial index and duplex sonography for occurrence of restenosis. Fibrinogen and serum amyloid A (SAA), as a control parameter of inflammation, were obtained at baseline, 8, 24 and 48 h postintervention. RESULTS: PTA (adjusted OR 3.1, p = 0.05) and stenting (adjusted OR 13.3, p = 0.001) were independently associated with a higher postintervention increase of fibrinogen compared to angiography. Restenosis was found in 29 patients (21%). Patients with pre-intervention fibrinogen values in the third quartile (411-463 mg/dl) had a 6.2-fold increased adjusted risk for restenosis (p = 0.03), patients in the fourth quartile (> 463 mg/dl) had a 8.9-fold increased adjusted risk (p = 0.007). Pre-intervention SAA values were also significantly associated with restenosis (p < 0.0001). Postintervention fibrinogen and SAA levels showed no association with outcome. CONCLUSION: Balloon angioplasty and stenting of the iliac arteries cause an elevation of postintervention fibrinogen levels independently of angiographic factors. A higher pre-procedure fibrinogen level, presumably a marker of inflammatory activity, indicates a higher risk for restenosis.

Aged↗

PubMed2001

C4d-positive acute humoral renal allograft rejection: effective treatment by immunoadsorption.

There is increasing evidence for an important pathogenetic role of alloantibodies in acute renal allograft rejection. Acute humoral rejection (AHR) has been reported to be associated with a poor transplant survival. Although treatment modalities for cellular rejection are fairly well established, the optimal treatment for AHR remains undefined. Ten of 352 kidney allograft recipients transplanted at the authors' institution between November 1998 and September 2000 were diagnosed as having AHR, supported by severe graft dysfunction, C4d deposits in peritubular capillaries (PTC), and accumulation of granulocytes in PTC. AHR was diagnosed 18.9 +/- 17.5 d posttransplantation. All patients were subjected to immunoadsorption (IA) with protein A (median number of treatment sessions, 9; range, 3 to 17). Seven recipients with additional signs of cellular rejection (according to the Banff classification) received also antithymocyte globulin. In nine of ten patients, AHR was associated with an increase in panel reactive antibody reactivity. A pathogenetic role of alloantibodies was further supported by a positive posttransplant cytotoxic crossmatch in all tested recipients (n = 4). In nine of ten recipients, renal function recovered after initiation of anti-humoral therapy. One patient lost his graft shortly after initiation of specific therapy. Another recipient with partial reversal of AHR returned to dialysis 8 mo after transplantation. Mean serum creatinine in functioning grafts was 2.2 +/- 1.2 mg/dl after the last IA session (n = 9) and 1.5 +/- 0.5 mg/dl after a follow-up of 14.2 +/- 7.1 mo (n = 8). In conclusion, this study suggests that AHR, characterized by severe graft dysfunction, C4d staining, and peritubular granulocytes, can be effectively treated by timely IA. In the majority of patients, IA treatment can restore excellent graft function over a prolonged time period.

Acute Disease↗

PubMed2001

Flow cytometric crossmatching in primary renal transplant recipients with a negative anti-human globulin enhanced cytotoxicity crossmatch.

Flow cytometric crossmatching (FCXM) and panel reactive antibody (PRA) screening techniques are more sensitive than anti-human globulin enhanced cytotoxicity (AHG-CDC) techniques at detecting anti-HLA antibodies. The clinical significance of a positive FCXM in primary renal transplant recipients with a negative AHG-CDC crossmatch is unclear. We performed retrospective FCXM and flow cytometric panel reactive antibody (FlowPRA) determinations in primary renal transplant recipients with a negative T cell AHG-CDC crossmatch and a negative B cell CDC crossmatch pretransplant. Eighteen (13%) of 143 patients exhibited a positive retrospective T cell FCXM. Of these patients, six (33%) experienced early graft loss with explant histology, demonstrating antibody-mediated rejection in five of six cases. The 12 patients with positive T cell FCXM who maintained their grafts experienced more adverse events posttransplant, including more early, steroid-resistant, and recurrent rejection. Furthermore, in a subgroup of patients undergoing protocol biopsies, those with a positive T cell FCXM exhibited more subclinical rejection. Anti-HLA antibodies were detected by FlowPRA in all 18 patients with a positive T cell FCXM, whereas AHG-CDC PRA detected antibodies in only 8 of 18 patients. Therefore, flow cytometric techniques identify sensitized primary renal transplant recipients undetected by AHG-CDC techniques. In those patients, a positive T cell FCXM is associated with an increased risk of early graft loss due to antibody-mediated rejection and may represent a relative contraindication to transplantation. Moreover, those patients are also at increased risk of severe and recurrent rejection, which may carry implications for long-term graft outcomes.

Adult↗