Brent T. Allen

Diagnosis of Perioperative Myocardial Infarction with Measurement of Cardiac Troponin I

BACKGROUND Perioperative myocardial infarction is the most common cause of morbidity and mortality in patients who have had noncardiac surgery, but its diagnosis can be difficult. The present study was designed to determine whether the measurement of serum levels of cardiac troponin I, a highly sensitive and specific marker for cardiac injury, would help establish the diagnosis of myocardial infarction. METHODS We obtained preoperative measurements of MB creatine kinase, total creatine kinase, and cardiac troponin I, in addition to base-line electrocardiograms and two-dimensional echocardiograms, in 96 patients undergoing vascular surgery and 12 undergoing spinal surgery. Blood samples were obtained every 6 hours for at least the first 36 hours after surgery, and electrocardiograms were obtained daily; a second echocardiogram was obtained approximately three days after surgery. The appearance of a new abnormality in segmental-wall motion on the postoperative echocardiogram (that is, an abnormality that had not been seen on the preoperative echocardiogram) was considered to be indicative of perioperative infarction. RESULTS Eight patients who underwent vascular surgery had new abnormalities in segmental-wall motion and received a diagnosis of perioperative infarction. All eight had elevations of cardiac troponin I, and six had elevations of MB creatine kinase. Of the 100 patients without perioperative infarction detected by echocardiography, 19 had elevations of MB creatine kinase, and 1 had a slight elevation of cardiac troponin I. CONCLUSIONS The measurement of cardiac troponin I is a sensitive and specific method for the diagnosis of perioperative myocardial infarction. It avoids the high incidence of false diagnoses associated with the use of MB creatine kinase as a diagnostic marker.

Preoperative treatment with doxycycline reduces aortic wall expression and activation of matrix metalloproteinases in patients with abdominal aortic aneurysms

PURPOSE Matrix metalloproteinases (MMPs) are considered to play a central role in the pathogenesis of abdominal aortic aneurysms (AAAs). Doxycycline (Dox) has direct MMP-inhibiting properties in vitro, and it effectively suppresses the development of elastase-induced AAAs in rodents. The purpose of this study was to determine if treatment with Dox suppresses MMPs within human aneurysm tissue and to elucidate the molecular mechanisms underlying this effect. METHODS Aneurysm tissues were obtained from 15 patients with an AAA, eight of whom had been treated with Dox before surgery (100 mg orally twice a day for 7 days). Protein extracts were examined by means of gelatin zymography and immunoblot analysis, and RNA was examined by means of reverse transcription-polymerase chain reaction (RT-PCR). The effects of Dox on MMP production were further examined in human THP-1 mononuclear phagocytes in vitro. RESULTS No detectable difference was found between groups by using substrate zymography as a means of assessing total MMP activity, but Dox treatment was associated with a slight (24.4%) reduction in the activated fraction of 72-kDa gelatinase (MMP-2; P <.05). In contrast, a 2.5-fold reduction in the amount of extractable 92-kDa gelatinase (MMP-9) protein in Dox-treated patients was revealed by means of immunoblot analysis (P <.05). Also, a 5.5-fold (81.9%) reduction in MMP-9 messenger RNA (mRNA) in Dox-treated patients was demonstrated by means of quantitative competitive RT-PCR (mean +/- SE, mol MMP-9/mol beta-actin: 1.3 +/- 0.5 vs 7.2 +/- 3.1; P <.04). There was no significant difference between groups in the relative expression of MMP-2 protein or mRNA. In cultured THP-1 monocytes stimulated with phorbol ester, the expression of MMP-9 protein and mRNA were both decreased after exposure to relevant concentrations of Dox in vitro. CONCLUSION In addition to its recognized effects as a direct MMP antagonist, Dox may influence connective tissue degradation within human aneurysm tissue by reducing monocyte/macrophage expression of MMP-9 mRNA and by suppressing the post-translational processing (activation) of proMMP-2. Through this complementary combination of mechanisms, treatment with Dox may be a particularly effective strategy for achieving MMP inhibition in patients with an AAA.

Transabdominal versus retroperitoneal incision for abdominal aortic surgery: Report of a prospective randomized trial ☆ ☆☆ ★

PURPOSE The purpose of this study was to perform a randomized, prospective trial that compares the transabdominal with the retroperitoneal approach to the aorta for routine infrarenal aortic reconstruction. METHODS From August 1990 through November 1993, patients undergoing surgery for abdominal aortic aneurysm (AAA) disease or aortoiliac occlusive disease (AIOD) were asked to participate in a randomized trial comparing the transabdominal incision (TAI) to the retroperitoneal incision (RPI) for aortic surgery. One hundred forty-five patients were randomized, with 75 (41 with AAA and 34 with AIOD) in the TAI group and 70 (40 with AAA and 30 with AIOD) in the RPI group. There were no significant differences between the groups in terms of age, sex, postoperative pain control (epidural vs patient-controlled analgesia), or comorbid conditions, except for a higher incidence of chronic obstructive pulmonary disease in the TAI group (21 vs 8 patients). RESULTS The incidence of intraoperative complications was similar for both groups. After surgery, the incidence of prolonged ileus (p = 0.013) and small bowel obstruction (p = 0.05) was higher in the TAI group. Overall, the RPI group had significantly fewer complications (p < 0.0001). The overall postoperative mortality rate (two deaths) was 1.4%, with both occurring in the TAI group (p = 0.507). The RPI group also had significantly shorter stays in the intensive care unit (p = 0.006), a trend toward shorter hospitalization (p = 0.10), lower total hospital charges (p = 0.019), and lower total hospital costs (p = 0.017). There was no difference in pulmonary complications (p = 0.71). In long-term follow-up (mean 23 months), the RPI group reported more incisional pain (p = 0.056), but no difference was found in incisional hernias or bulges (p = 0.297). CONCLUSIONS We conclude that the RPI approach for abdominal aortic surgery is associated with fewer postoperative complications, shorter stays in the hospital and intensive care unit, and lower cost. There is, however, an increase in long-term incisional pain. Current methods of postoperative pain control seem to decrease the incidence of pulmonary complications.

Spontaneous closure of selected iatrogenic pseudoaneurysms and arteriovenous fistulae

PURPOSE We report our approach to the management of postcatheterization femoral artery pseudoaneurysms and arteriovenous fistulae in an attempt to determine the frequency of spontaneous resolution of selected lesions. METHODS We studied 196 pseudoaneurysms, 81 arteriovenous fistulae, and 9 combined lesions that were identified by duplex scan. Indications for immediate surgical repair included pseudoaneurysm greater than 3 cm, enlarging hematoma, pain, groin infection, nerve compression, limb ischemia, concomitant surgical procedure, and patient refusal or inability to comply with follow-up. All other lesions were observed. RESULTS One hundred thirty-nine patients underwent prompt surgical repair, and 147 patients were initially managed without operation. There were no limb-threatening complications associated with nonoperative management in this subset of patients. Eighty-six percent of the lesions being observed resolved spontaneously within a mean of 23 days, whereas 14% required surgical closure for a variety of reasons (at a mean of 111 days after the initial diagnosis). There was no statistically significant difference in the rate of spontaneous pseudoaneurysm closure (89%) as opposed to fistulae (81%) (p < 0.17). By life-table analysis, 90% of selected pseudoaneurysms had resolved by 2 months. Patients selected for observation underwent an average of 2.6 duplex scans per patient versus 1.4 scans per patient for those treated with immediate surgery (p < 0.01). CONCLUSION The natural history of stable pseudoaneurysms and arteriovenous fistulae is benign and frequently results in spontaneous resolution, which allows properly selected patients to be managed without operation.

The influence of anesthetic technique on perioperative complications after carotid endarterectomy

Abstract Purpose: This study evaluated the influence of anesthetic techniques on perioperative complications after carotid endarterectomy. Methods: Perioperative complications, the use of a carotid artery shunt, the duration of the operative procedure and postoperative hospital course were retrospectively compared in 584 consecutive patients undergoing 679 carotid endarterectomies with use of either general anesthesia ( n = 361) or cervical block regional anesthesia ( n = 318). There was no significant difference in the preoperative medical characteristics between the two anesthetic groups. Symptomatic carotid artery disease was the indication for surgery in 247 (68.4%) patients receiving general anesthetics, whereas 180 (56.6%) patients treated with a cervical block anesthetic had a symptomatic carotid artery stenosis ( p = 0.02). Results: The perioperative stroke rate and stroke-death rate for the entire series was 2.4% and 3.2%, respectively, and was not significantly different between the anesthetic groups or between patients with symptomatic or asymptomatic disease. A carotid artery shunt was used in 61 (19.2%) patients receiving a cervical block anesthetic and 152 (42.1%) patients treated with a general anesthetic ( p p = 0.04). Conclusions: We conclude that cervical block anesthesia is safer and results in a more efficient use of hospital resources than general anesthesia in the treatment of patients undergoing carotid endarterectomy. (J VASC SURG 1994;19:834-43.)

Influence of endothelial cell seeding on platelet deposition and patency in small-diameter Dacron arterial grafts

Serial platelet deposition, surface topography, and patency were evaluated in control (N = 28) and endothelial cell-seeded (N = 28) small-diameter (4 mm inner diameter) USCI Dacron grafts implanted in the carotid and femoral arteries of dogs. All dogs received aspirin (325 mg) daily for 2 weeks starting 24 hours prior to graft implantation. Endothelial cell seeding was performed by mixing suspensions of autologous endothelial cells that had been enzymatically harvested from segments of external jugular vein with blood that was used to preclot the prostheses. The platelet deposition on each graft was quantitated by means of indium 111-labeled platelets and technetium 99m-labeled red cells in a dual-isotope platelet-imaging technique. Platelet deposition on seeded grafts 24 hours after implantation was significantly higher than on the controls (p less than 0.05). Two weeks after implantation platelet deposition on seeded prostheses had decreased to a level significantly lower than that on the controls and continued to decline on serial studies up to 7 months. In contrast to seeded grafts, platelet accumulation on control grafts dramatically increased after the withdrawal of aspirin therapy and was associated with a sharp rise in control graft thromboses. Gross and scanning electron microscopic evaluation of endothelial cell-seeded grafts after 1 month indicated complete neointimal coverage, whereas none of the control grafts explanted at 1 month or later exhibited a continuous neointimal lining. Cumulative 7-month patency for seeded prostheses was significantly higher than for the controls (96% and 29%, respectively; p less than 0.001). We conclude that endothelial cell seeding in combination with short-term aspirin therapy is a simple, reliable diameter Dacron prostheses. Abrupt withdrawal of aspirin therapy may be contraindicated in nonseeded control grafts because it results in increased platelet deposition and thrombosis.

Preservation of renal function in juxtarenal and suprarenal abdominal aortic aneurysm repair

PURPOSE Deterioration in renal function is a common cause of morbidity in patients treated surgically for juxtarenal and suprarenal abdominal aortic aneurysms. We reviewed our experience over the last 8 years with 65 consecutive patients undergoing juxtarenal (n = 31) or suprarenal (n = 34) abdominal aortic aneurysm repair. METHODS The aneurysms were repaired with a transabdominal (n = 8), thoracoabdominal (n = 4), retroperitoneal (n = 22), or thoracoretroperitoneal (n = 31) approach. Proximal aortic clamps were placed at the suprarenal, supra-superior mesenteric artery, or supraceliac level. Renal hypothermia with cold heparinized saline solution renal artery perfusion was used to protect renal function in 38 patients with either preoperative renal insufficiency or with anticipated prolonged renal ischemia (> 30 minutes). Concomitant renal artery reconstruction was required in 30 patients. RESULTS Significant operative morbidity developed in 23 (35.3%) patients. There was one (1.53%) perioperative death (0 to 90 days). Temporary dialysis was necessary in two patients. Preoperative renal insufficiency was a significant risk factor on multivariate analysis for a decline in renal function during the first postoperative week. However, serum creatinine concentration had returned to baseline or improved in all patients but two (3.1%) at the time of discharge. In spite of significantly longer renal ischemia, discharge creatinine levels were, on univariate analysis, statistically less than baseline creatinine levels in patients with suprarenal aneurysms, patients requiring renal reconstruction, and patients treated with renal hypothermia. The location of the proximal aortic clamp was not a factor in postoperative morbidity. There was no significant difference between juxtarenal and suprarenal aneurysms with respect to operating room time, transfusion requirements, days intubated, resumption of oral diet, or the length of hospitalization. CONCLUSIONS Careful consideration of the route of exposure, location of the proximal aortic clamp, and the preservation of renal function with renal hypothermia and with the repair of significant renal artery lesions will result in minimal morbidity and mortality in patients requiring surgery for juxtarenal or suprarenal abdominal aortic aneurysms.

Autologous vein–covered stent for the endovascular management of an iliac artery–ureteral fistula: Case report and review of the literature

Iliac artery-ureteral fistula is a rare entity that is being reported with increasing frequency. Patients with iliac artery-ureteral fistulas can be divided into two distinct groups on the basis of the factors that predispose them to having these fistulas. In group I the fistula is associated with degenerative iliac artery disease or previous arterial reconstructive surgery. Patients in group II have undergone some combination of the following procedures: pelvic extirpative surgery for malignancy, urinary diversion, radiation therapy, and ureteral stenting. The diagnosis of an iliac artery-ureteral fistula can be elusive even with the use of multiple imaging methods. Direct operative repair is technically demanding and is associated with high mortality rates. In recent years, treatment has shifted toward percutaneous embolization of the iliac artery and extraanatomic lower extremity vascular reconstruction for group II patients. In this report, the 24 group II patients with iliac artery-ureteral fistulas who previously have been described are reviewed, and a new endovascular treatment for this entity that uses a stented vein graft is detailed.

Therapeutic Footwear Can Reduce Plantar Pressures in Patients With Diabetes and Transmetatarsal Amputation

OBJECTIVE To compare how footwear (full-length shoe or short shoe), a total contact insert, a rigid rocker-bottom (RRB) sole, and an ankle-foot orthosis (AFO) affect peak plantar pressure (PPP) on the distal residuum and contralateral extremity of patients with diabetes and transmetatarsal amputation (TMA). RESEARCH DESIGN AND METHODS Thirty patients with diabetes and TMA participated (mean age 62 ± 4 years). In-shoe plantar pressures during walking were measured in six types of footwear. Each measurement occurred after a 1-month adjustment period. Repeated measure analysis of variance (ANOVA) was used to compare treatments. RESULTS All five types of therapeutic footwear reduced plantar pressures compared with regular shoes with a toe-filler (P < 0.05). A full-length shoe, total contact insert, and RRB sole resulted in lower pressures on the distal residuum (222 vs. 284 kPa) and forefoot of the contralateral extremity (197 vs. 239 kPa), compared with a regular shoe and toe-filler. Footwear with an AFO showed reduced PPP on the residuum, but most patients complained of reduced ankle motion during walking. A short shoe reduced pressures on the residuum, but not on the contralateral extremity, and many patients had complaints regarding cosmesis of the shoe. CONCLUSIONS The full-length shoe, total contact insert, and an RRB sole provided the best pressure reduction for the residuum and contralateral foot, with the optimal compromise for cosmetic acceptance and function.

Intraoperative salvage in patients undergoing elective abdominal aortic aneurysm repair: An analysis of cost and benefit

PURPOSE Although autologous blood procurement has become a standard of care in elective surgery, recent studies have questioned its cost-effectiveness. We therefore reviewed our 3-year experience with intraoperative cell salvage in patients who underwent elective abdominal aortic aneurysm repair. METHODS A 3-year retrospective chart review of elective abdominal aortic aneurysm (infrarenal and suprarenal) repair was performed. Transthoracic repairs were excluded. RESULTS Estimated blood lost was 1748 +/- 1236 ml, or 35% of baseline blood volume (5012 +/- 689 ml). Overall, 164 (89%) received red blood cell (RBC) transfusions (3.5 +/- 2.0 U/patient). The cost per patient for cell salvage was