The accurate assessment of coagulation status is an important part of interventional procedures performed in the cardiac catheterization laboratory. While the traditional clinical means of assessing heparin anticoagulation has been with the activated partial thromboplastin time (APTT), the activated coagulation time (ACT) has come into widespread use in the catheterization laboratory as an assay of whole blood clotting time which can be performed rapidly at the bedside. The purpose of the present study was to (1) assess the anticoagulant effect of a 10,000 U bolus of heparin in PTCA patients and (2) document the relationship between ACTs and APTTs in a subset of these patients. Baseline and postheparin ACTs were measured using a HemoTec coagulation timer in 545 unselected PTCA patients. The average baseline ACT was 120 +/- 22 sec. After a 10,000 U bolus of heparin the average ACT was 249 +/- 44 sec; 58% of patients had an ACT less than 250 sec, 17% had an ACT between 250 and 275 sec, 12% had an ACT between 275 and 300 sec, and 13% had an ACT greater than 300 sec. A total of 175 paired ACT and APTT measurements were obtained in a random subset of these patients at baseline, after heparinization, and at 4-6 hr intervals after the procedure. The APTT was limited by absolute upper and lower limits of 150 and 22 sec; there were no such limits on the ACT. When limiting values were excluded, there was a strong overall correlation between ACT and APTT measurements (r = 0.92, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
The effective flow rates with human blood through an autoperfusion catheter cannot be monitored in vivo and have not been experimentally determined in vitro. The manufacturers (Advanced Cardiovascular Systems [ACS], Temecula, CA) have suggested that "the flow rate" through the Stack over the wire and the RX-60 monorail catheter is 60 ml/min with a pressure gradient of 80 mmHg. We measured human blood flow rates in vitro through these catheters under different continuous pressure regimens (between 40 and 120 mmHg), with varying hematocrit levels (between 25% and 62%). Measured blood flows at a gradient of 80 mmHg were found to vary from 32 to 65 cc/min, with hematocrit levels of 62-25%. Minor variations in the circuitry, besides the viscosity of the medium, cause significant changes in observed flow rates (such as kinking of the catheter and blood sedimentation). In vitro determinations of blood flows cannot automatically be transferred to the in vivo condition, primarily because in vitro determinations do not account for the systolic intramural pressure increase (which may overcome the aortic pressure). If such a phenomenon is also considered, then the in vitro flow rates reported here should be multiplied by a factor of 0.40-0.60 to determine effective in vivo flow rates. Such information is relevant for the clinical operator of angioplasty, especially in the treatment of patients at high risk for undergoing percutaneous transluminal coronary angioplasty.
We present a series of 4 patients in whom mechanical trauma was identified as a factor in the development of late complications after AneuRx Stent Graft placement for repair of abdominal aortic aneurysms. In all 4 patients, Type I or III endoleaks (and pseudoaneurysms in 2 patients) were discovered several months after abdominal aortic aneurysm repair with the AneuRx device. Two patients had sustained blunt abdominal trauma in a car accident one had suffered a traumatic fall, and another had been participating in vigorous rowing activity. In all patients, the trauma had occurred several months before the diagnosis of endoleak or pseudoaneurysm (or both) was established. In all patients, follow-up computed tomographic scans identified the complications. In conclusion, blunt mechanical injury is an unrecognized factor contributing to the late failure of endovascular stent grafts. Vigorous physical activity may also contribute to graft disruption or to the separation of modular components.
Historically, open surgical repair of thoracoabdominal aortic aneurysms has been associated with high morbidity and mortality rates. Furthermore, endovascular exclusion alone can restrict blood flow to visceral arteries. We report a case of thoracoabdominal aortic aneurysm that was repaired using a hybrid approach: surgery followed by an endovascular procedure. A 53-year-old woman was admitted to our hospital for endovascular exclusion of a thoracoabdominal aortic aneurysm that included the superior mesenteric artery and the celiac artery. Aorto-mesenteric and aorto-celiac artery bypass grafting was performed to create a landing zone for subsequent endovascular exclusion of the aneurysm, which was completed successfully 6 weeks after the bypass procedure. For thoracoabdominal aortic aneurysms that extend beyond the superior mesenteric artery and the celiac or renal arteries, a hybrid approach, consisting of limited surgical treatment followed by endovascular exclusion of the aneurysm, may yield optimal results in selected patients with serious preoperative comorbidities.
PURPOSE To report a case of late stent-graft infection with aortoenteric fistula. CASE REPORT A 76-year-old Colombian man received an AneuRx stent-graft for a 5.5-cm infrarenal AAA. The aneurysm sac progressively shrank until 22 months postoperatively, when an increase in diameter was noted on magnetic resonance imaging without evidence of endoleak or air in the sac. Two months prior, the patient had developed fever and an elevated white blood cell count; he underwent a 6-week course of intravenous antibiotics. Shortly thereafter, the fever recurred, along with progressive weight loss, which prompted admission. The computed tomographic scan showed no evidence of endoleak, but gas collection was seen anteriorly in the sac; aspirated material was positive for a variety of organisms. At surgery 23 months after stent-graft implantation, pronounced inflammatory reaction and scarring were seen around the graft in conjunction with evidence of a healed duodenal perforation, suggestive of an aortoenteric fistula. The excised stent-graft was intact; no deterioration was seen. The patient had a protracted recovery but has been afebrile and asymptomatic >1 year after stent-graft explantation CONCLUSIONS Close surveillance after endovascular AAA repair is essential to detect late leaks, secondary migration, endotension, structural failure, and infection with or without aortoenteric fistula.
