Jeffrey M. Slaiby

Expansion of aortic aneurysms is reduced by propranolol in a hypertensive rat model

PURPOSE It has been suggested that propranolol has unique effects that slow aneurysm expansion by remodeling the structural proteins of the aorta. These effects are believed to be independent of blood pressure reduction, a hypothesis we tested in this investigation with a rat model of abdominal aortic aneurysm (AAA). METHODS With an established model, AAA were induced in normotensive Wistar-Kyoto (WKY) rats and genetically hypertensive Wistar-Kyoto (WKHT) rats by perfusing an isolated segment of the infrarenal aorta with elastase. A propranolol dose-response was studied for each strain: (1) saline solution controls (n = 18); (2) propranolol, 10 mg/kg subcutaneously (n = 18); (3) propranolol, 30 mg/kg (n = 14). Systolic blood pressure was determined by tail plethysmography before operation and on day 14, as well as by direct recording at surgery and on day 14. Rats were killed at 14 days, and aneurysm diameter was measured. RESULTS The initial tail BP was 129 +/- 22 mm Hg in WKY animals and 158 +/- 21 mm Hg in WKHT animals (p < 0.0001). Tail BP and intraaortic systolic, diastolic, and mean blood pressure (BP) were not significantly decreased by propranolol treatment in either strain of rats. However, BP tended to rise in WKY rats, whereas it fell slightly in WKHT rats. Initial aortic size in all animals was 1.06 +/- 0.12. The final aortic size in untreated, hypertensive rats was more than twice that of untreated normotensive controls: 1: WKHT, 3.0 +/- 0.73 mm, 1: WKY, 6.9 +/- 3.5 mm (p < 0.01). After treatment with both doses of propranolol, hypertensive aneurysms were significantly smaller than the untreated WKHT group (p < 0.05) and not significantly different from aneurysms in all groups of normotensive animals: 2: WKY, 3.1 +/- 1.13 mm, 2: WKHT, 4.0 +/- 1.81 mm; 3: WKY, 4.1 +/- 0.41 mm, 3: WKHT, 2.9 +/- 1.24 mm. There was no significant difference in aortic size between the three normotensive WKY groups. CONCLUSIONS Hypertension increases the size of aortic aneurysms in this experimental model. Propranolol significantly reduces the size of experimental AAA in hypertensive animals independently of the dose and by a mechanism that may be unrelated to simple BP reduction.

Predictors of shunt during carotid endarterectomy with routine electroencephalography monitoring

BACKGROUND The routine use of intraoperative electroencephalography (EEG) monitoring with selective shunt placement during carotid endarterectomy (CEA) has been shown to be safe and effective. We attempt to identify the anatomic and clinical factors associated with significant EEG changes requiring shunt placement during CEA. METHODS Between January 2005 and June 2007, 242 CEAs were performed with selective shunt placement for significant EEG changes. Risk factors assessed include severity of both ipsilateral and contralateral disease, presence of ipsilateral preoperative symptoms, hypertension, coronary artery disease, diabetes, age, gender, and preemptive intraoperative blood pressure manipulation to >or=20% above baseline before cross-clamping. Data were analyzed with the chi(2) test (P < .05 was significant). RESULTS CEA was performed for asymptomatic disease in 177 of 242 patients (73.1%). The perioperative stroke rate was 0.8% (2 of 242), and the overall morbidity rate was 4.5%. No patients died. Significant EEG changes requiring shunt occurred in 35 patients (14.46%). Factors associated with carotid shunt placement were moderate ipsilateral carotid artery stenosis (50% to 79%) compared with severe (>or=80%) disease (30.6% vs 11.7%, P = .003) and degree of contralateral carotid stenosis (0% to 49%, 10.8%; 50% to 79%, 10.9%; 80% to 99%, 23.2%; occlusion, 50%; P = .0003). Presence of symptoms, gender, age, hypertension, diabetes, or coronary artery disease, and preemptive intraoperative manipulation of blood pressure were not significant predictors of shunt placement. CONCLUSION CEA performed with routine EEG monitoring and selective shunt placement is associated with a low risk of perioperative stroke. Identified predictors of significant EEG changes were anatomic factors including degree of contralateral carotid artery disease and moderate ipsilateral carotid artery stenosis (50% to 79%). Although contralateral carotid occlusion has been accepted as indication for shunt placement in the absence of cerebral monitoring, this study suggests that high-grade contralateral disease and moderate ipsilateral carotid stenosis are associated with cerebral ischemia resulting in EEG changes and should prompt consideration for nonselective shunting.

A 14-year experience with blunt thoracic aortic injury

OBJECTIVE This study reviewed the natural history of blunt thoracic aortic trauma (BTAT) over a 14-year period at our level 1 trauma center and compared open vs endovascular treatment. METHODS All patients with BTAT presenting to a level 1 trauma center from 1998 to 2011 were included in a retrospective analysis. Multiple data points and short-term and midterm outcomes were ascertained through a retrospective record review. RESULTS We identified 129 patients with BTAT. Of these, 32 (25%) were dead on arrival, 38 (29%) underwent a resuscitative thoracotomy and died, 33 (26%) underwent open repair, 14 (11%) underwent endovascular repair, 9 (7%) underwent simultaneous procedures, and 3 (2%) were managed nonoperatively. Mean Injury Severity Scores and Revised Trauma Scores were similar (P = .484, P = .551) between the open repair group (n = 36) and the endovascular repair group (n = 14). In the open repair group, there were 14 deaths (42%) ≤ 30 days of injury, 3 strokes (9%), 2 patients (6%) with paralysis, 2 myocardial infarctions (MIs; 6%), and 3 patients (9%) who required hemodialysis. In the endovascular group, there was 1 death (7%) ≤ 30 days of injury, 1 (7%) stroke, and 1 (7%) stent collapse. No paralysis, MI, or renal failure requiring hemodialysis was noted in the endovascular group. The average length of stay was 15 days for patients treated with endovascular repair vs 24 days for those treated with open repair (P = .003). CONCLUSIONS The incidence of BTAT is low but the mortality associated with it is significant. During the 14-year period studied, there was a clear change in management preference from open repair to endovascular repair at our level 1 trauma center. Outcomes, including stroke, MI, renal failure, paralysis, length of stay, and death, appear to be reduced in the endovascular group.

Open Revascularization Procedures Are More Likely to Influence Smoking Reduction Than Percutaneous Procedures

BACKGROUND Among patients with peripheral arterial disease (PAD), smokers have a higher incidence of life- and limb-threatening complications, including lower extremity ischemic rest pain, myocardial infarction, and cardiac death, highlighting the need for smoking reduction. Several studies have previously investigated the perioperative period as a teachable moment for smoking cessation. The purpose of this study is to determine whether the type of revascularization for PAD (percutaneous versus open) is associated with smoking reduction. METHODS Study participants included patients seen at a tertiary academic medical center in Providence, RI, between 2005 and 2010 and assigned International Classification of Diseases, Ninth Revision code diagnoses indicative of PAD. This study uses patient-answered surveys and retrospective chart review to assess changes in smoking habits after medical, percutaneous, or open revascularization. Surveys also assessed patient perceptions regarding the influence of intervention on smoking reduction and how strongly patients associate PAD with their smoking habits. RESULTS Of 54 patients who were active smokers at the time of intervention, 8 (67%) in the medical management group, 12 (50%) in the percutaneous group, and 15 (83%) in the open intervention group reduced smoking by 50% after intervention. After controlling for several confounders, open revascularization was independently associated with smoking reduction when compared with percutaneous intervention (odds ratio, 8.26; 95% confidence interval, 1.18, 76.7; P = 0.043). Surveys revealed that 94% of the patients believed that smoking was a significant contributor to their PAD. CONCLUSIONS Patients with PAD who undergo open revascularization are more likely to reduce smoking than those who undergo percutaneous revascularization. The perioperative period provides an opportunity to improve rates of smoking reduction.

Hemodynamic and Biochemical Characteristics of the Aorta in the WKY, SHR, WKHT, and WKHA Rat Strains

This study was designed to characterize the hemodynamic and biochemical properties of the abdominal aorta in four genetically related inbred rat strains that express genetic hypertension and hyperactive behavior in varying combinations. These include (1) the spontaneously hypertensive rat (SHR), which is hypertensive, hyperactive, and hyperreactive to stress; (2) Wistar-Kyoto (WKY) rats, which express none of these traits; (3) WKHT rats, which are hypertensive but not hyperactive; and (4) WKHA rats, which are hyperactive and hyperreactive to stress, but normotensive. Together, these four strains allowed us to examine the structural and functional changes in the aorta in the hypertensive SHR, the most widely used animal model of genetic hypertension, while controlling for the variables of hyperactivity and hyperreactivity that are also expressed in the SHR. Four groups of animals of both sexes were studied: (1) WKY, n = 101, (2) WKHA, n = 33, (3) WKHT, n = 91, and (4) SHR, n = 28. Blood pressure (BP) was determined by tail plethysmography as well as direct intraarterial monitoring under anesthesia. Fixed specimens were prepared for histologic analysis and the wall thickness determined morphometrically. Quantification of soluble tissue protein, elastin, and collagen in the aortic tissue was determined by measuring leucine (leu), hydroxyproline (HP/leu), and desmosine (DES/leu). The hypertensive strains (SHR and WKHT) had significantly higher tail BP than the normotensive strains (WKY and WKHA)-WKY: 128.7 +/- 22.3; WKHA: 126.7 +/- 14.6; WKHT: 162.8 +/- 21.2; SHR: 164.2 +/- 36.1 (p < 0.0001). Additionally, intraaortic diastolic BP and mean BP were higher in SHR rats than in WKHT. Morphometric studies showed the media thickness in the SHR rats was significantly greater than in the WKY and WKHA rats and no different than in the WKHT rats. Significantly less of the aortic wall protein was present as elastin in the hypertensive rats (SHR and WKHT), as well as the hyperactive rats (WKHA), compared to rats that had neither trait (WKY). These studies provide new information regarding aortic structure and function in genetic hypertension using inbred strains to control for the hyperactivity/hyperreactivity traits that coexist with hypertension in the SHR. They reveal that hypertensive aortas have altered matrix proteins that cannot be explained simply on the basis of blood pressure alone.

Bilateral Deep Femoral Vein Thrombosis

Introduction Deep vein thrombosis (DVT) is a major national health problem, especially among the critically ill and elderly. Most clinically significant DVTs involve the proximal veins of the lower limb, particularly the iliac, common femoral, femoral, and popliteal veins. Case Study We report a 53-year-old man sent to our vascular laboratory for ultrasound examination of the lower extremities to investigate the cause of nonpitting edema in both lower extremities. The ultrasound examination revealed isolated bilateral thrombosis in the deep femoral veins. Conclusion This is the first reported case of bilateral isolated deep femoral vein thrombosis.