Submaximal suppression of parathyroid hormone ameliorates calcitriol-induced aortic calcification and remodeling and myocardial fibrosis in uremic rats.

BACKGROUND AND OBJECTIVE: In subtotally nephrectomized rats, we studied to what extent high-dose calcitriol-induced cardiovascular disease can be modulated by almost complete suppression of parathyroid hormone (PTH), mediated by either cinacalcet (CINA) or parathyroidectomy (PTX). METHODS: Five groups were studied: sham-operated controls, uremic (U), uremic with calcitriol (U+1,25D), uremic and calcitriol with CINA (U+1,25D+CINA) and uremic and calcitriol with PTX (U+1,25D+PTX). Treatments lasted 14 weeks. RESULTS: Compared with U group animals, PTH was significantly lower with calcitriol treatment and almost completely suppressed in animals treated with either PTX or CINA. Serum calcium and phosphorus levels were similarly elevated in all groups receiving calcitriol. Renal function in uremic animals was significantly more impaired in the U+1,25D group. Aortic calcifications were pronounced in U+1,25D animals and reduced by more than 50% by concomittant treatment with CINA or PTX. Chondrocytes were observed near areas of calcification (>90%) and endochondral bone formation was confirmed by positive immunofluorescence for chondrocytic transcription factor sox9 and matrix protein collagen X. Altered arterial (aneurysmatic) geometry with a significant increase in wall/lumen and lumen/body weight ratio was found only in the U+1,25D group. Myocardial fibrosis was present in all uremic groups with a significant increase in the U+1,25D group. Connective tissue growth factor messenger RNA was significantly upregulated only in the U+1,25D group. CONCLUSION: Submaximal suppression of PTH by either CINA or PTX reduced vascular calcifications, arterial remodeling and myocardial fibrosis to a similar degree and independent of the serum calcium and phosphorus levels. These data do not indicate vasculotropic effects of calcimimetics independent of PTH suppression.

Acute Aortic Treatment Center.

Acute aortic syndromes are a life-threatening set of conditions that require rapid triage and intervention to obtain satisfactory outcomes. The Methodist Hospital is the first institution to establish an Acute Aortic Treatment Center (AATC) based on a clinical care pathway that expedites the care of acute aortic syndromes. This pathway has resulted in a 64% reduction in time to definitive therapy and a reduction in intensive care unit (ICU) length of stay. Establishment of a multidisciplinary pathway to treat acute aortic syndromes improves efficiency and enhances outcomes.

Aortobifemoral embolism in an 18-year old patient following cisplatin and 5-fluorouracil chemotherapy for nasopharyngeal carcinoma.

After cisplatin / 5-fluorouracil chemotherapy for nasopharyngeal carcinoma, an 18-year female patient developed aortobifemoral embolism. Besides chemotherapy, additional risk factors for arterial thromboembolic events were smoking, contraceptive medication and adjuvant antiemetic treatment with dexamethasone. Thrombophilia screening was negative. Thromboembolic complications during or after cisplatin have been reported in a frequency of 17.6 % in lung cancer patients, and in 8.4 % of patients with germ cell tumors. The incidence of arterial thromboembolic events was 9.3 % and 1.7 %, respectively. The pathogenesis of cisplatin induced thromboembolism is thought to be caused by endothelial damage leading to endothelial cell dysfunction, increased von Willebrand factor plasma levels, and hypomagnesaemia.

Idiopathic ventricular arrhythmias originating from the aortic root prevalence, electrocardiographic and electrophysiologic characteristics, and results of radiofrequency catheter ablation.

OBJECTIVES: This study investigated the prevalence and electrocardiographic and electrophysiologic characteristics of aortic root ventricular arrhythmias (VAs). BACKGROUND: Idiopathic VAs originating from the ostium of the left ventricle may be ablated at the base of the aortic cusps. METHODS: We studied 265 patients with idiopathic VAs with an inferior QRS-axis morphology. RESULTS: The successful ablation site was within (or below) the aortic cusps in 44 patients (16.6%). The site of the origin was the left coronary cusp (LCC) in 24 (54.5%), the right coronary cusp (RCC) in 14 (31.8%), the noncoronary cusp (NCC) in 1 (2.3%), and at the junction between the LCC and RCC (L-RCC) in 5 (11.4%) cases. The maximum amplitude of the R-wave in the inferior leads was significantly greater with an LCC than with an RCC origin (p < 0.05). The ratio of the R-wave amplitude in leads II and III was significantly greater with an LCC than with an RCC origin (p < 0.01) and was significantly smaller in the NCC than in the other sites (p < 0.0001). The ventricular deflection in the His bundle electrogram was significantly later relative to the surface QRS with an LCC or L-RCC origin than with an RCC or NCC origin (p < 0.0001). The ratio of the atrial-to-ventricular deflection amplitude was significantly greater in the NCC than in the other sites (p < 0.0001). No other factors predicted the site of origin. CONCLUSIONS: Idiopathic VAs are more common in the LCC than in the RCC and rarely arise from the NCC. The electrocardiogram is useful for differentiating the site of origin.

Angiotensin receptor blockade with candesartan attenuates atherosclerosis, plaque disruption, and macrophage accumulation within the plaque in a rabbit model.

BACKGROUND: Little is known about whether direct angiotensin receptor blockade can reduce atherosclerosis and plaque disruption. This study evaluated the effect of angiotensin receptor blockade on both the development of atherosclerosis and the disruption of plaque in a modified Constantinides animal model. METHODS AND RESULTS: Twenty-eight New Zealand White rabbits underwent aortic balloon injury followed by a 1% cholesterol diet for 8 weeks. Thirteen rabbits received candesartan at 0.5 mg x kg(-1) x d(-1) beginning 2 days before aortic balloon injury and continued for the total 8 weeks of the cholesterol diet. The rabbits were then pharmacologically triggered and humanely killed, and their aortas were analyzed. The degree of atherosclerosis was determined by intima-media ratio of the infrarenal portion of the aorta. The frequency of intra-aortic thrombosis, a measure of plaque disruption, and the percentages of macrophage area and collagen-staining area of the plaque were determined. Candesartan-treated rabbits had less atherosclerosis (intima-media infrarenal aorta ratio of 1.18+/-0.08 versus 1.57+/-0.08 [mean+/-SEM] for the placebo group, P<0.001); fewer thrombi (3 of 13 versus 11 of 15; P<0.05); lower percentage area of macrophages to total plaque (18.8+/-2.7% versus 27+/-2.5%, P<0.05); and higher collagen to total plaque area (45+/-3% versus 35+/-2%, P<0.01). CONCLUSIONS: These results demonstrate that angiotensin receptor blockade attenuates the degree of atherosclerosis and reduces both plaque disruption and macrophage accumulation while increasing collagen deposition in the aortas of this animal model.

Autotransfusion in complex abdominal aneurysms.

We have used a simple adaptation of the cardiotomy suction apparatus for autotransfusion during operation for four aortocaval fistulas and two ruptured internal iliac aneurysms. This has allowed significant blood salvage and maintenance of intraoperative hemodynamic stability. We have had no intraoperative complications and have noted no renal or pulmonary compromise postoperatively. One patient had minor coagulopathy postoperatively that was corrected with fresh frozen plasma and platelet transfusion during the first 12 hours. Autotransfusion for aortocaval fistulas and ruptured internal iliac aneurysms is safe, simple, clinically beneficial and cost effective.

Aortocaval fistula associated with aneurysm of the abdominal aorta: current management using autotransfusion techniques.

Two patients with aortocaval fistula associated with abdominal aortic aneurysm were managed successfully using a patient care plan which includes proper monitoring of the hemodynamic state, careful dissection of the aneurysm, and return of blood loss by autotransfusion while the patient is fully anticoagulated with heparin. This unusual and serious problem in vascular surgery can be managed in an orderly and controlled fashion using these techniques.