Mohammed M. Moursi

Radial Artery Grafts vs Saphenous Vein Grafts in Coronary Artery Bypass Surgery: A Randomized Trial

CONTEXT Arterial grafts are thought to be better conduits than saphenous vein grafts for coronary artery bypass grafting (CABG) based on experience with using the left internal mammary artery to bypass the left anterior descending coronary artery. The efficacy of the radial artery graft is less clear. OBJECTIVE To compare 1-year angiographic patency of radial artery grafts vs saphenous vein grafts in patients undergoing elective CABG. DESIGN, SETTING, AND PARTICIPANTS Multicenter, randomized controlled trial conducted from February 2003 to February 2009 at 11 Veterans Affairs medical centers among 757 participants (99% men) undergoing first-time elective CABG. INTERVENTIONS The left internal mammary artery was used to preferentially graft the left anterior descending coronary artery whenever possible; the best remaining recipient vessel was randomized to radial artery vs saphenous vein graft. MAIN OUTCOME MEASURES The primary end point was angiographic graft patency at 1 year after CABG. Secondary end points included angiographic graft patency at 1 week after CABG, myocardial infarction, stroke, repeat revascularization, and death. RESULTS Analysis included 733 patients (366 in the radial artery group, 367 in the saphenous vein group). There was no significant difference in study graft patency at 1 year after CABG (radial artery, 238/266; 89%; 95% confidence interval [CI], 86%-93%; saphenous vein, 239/269; 89%; 95% CI, 85%-93%; adjusted OR, 0.99; 95% CI, 0.56-1.74; P = .98). There were no significant differences in the secondary end points. CONCLUSION Among Veterans Affairs patients undergoing first-time elective CABG, the use of a radial artery graft compared with saphenous vein graft did not result in greater 1-year patency. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00054847.

Surgical complications from hemostatic puncture closure devices

BACKGROUND For securing immediate hemostasis following percutaneous arterial catheterization, the Food and Drug Administration has approved three hemostatic puncture closure devices. We reviewed our institutional experience with one device (Angio-Seal). METHODS A retrospective, single-center, nonrandomized observational study was made of all vascular complications following femoral cardiac catheterization. RESULTS An immediate mechanical failure of the device was experienced in 34 (8%) patients. Surgical repair was required in 1.6% (7 of 425) of patients following Angio-Seal versus 0.3% (5 of 1662) following routine manual compression (P = 0.004). In 5 patients, the device caused either complete occlusion or stenosis of the femoral artery. The polymer anchor embolized in 1 patient and was retrieved with a balloon catheter at surgery. CONCLUSION During the first year of utilization of a percutaneous hemostatic closure device following cardiac catheterization, we observed a marked increase in arterial occlusive complications requiring surgical repair. Surgeons must be familiar with the design of these devices to achieve precise repair of surgical complications.

Microbubble-augmented Ultrasound Declotting of Thrombosed Arteriovenous Dialysis Grafts in Dogs

PURPOSE Transcutaneous low-frequency ultrasound (LFUS) can effectively lyse clots in the presence of microbubbles. This study was designed to test the commercially available human albumin microspheres injectable suspension octafluoropropane formulation, Optison, to establish efficacy and assess US parameters of intensity and wave modes in a canine model of a thrombosed arteriovenous (dialysis) graft. MATERIALS AND METHODS Arteriovenous grafts in five dogs were cannulated, temporarily ligated, and thrombosed. Different declotting techniques were randomized to treat nine groups. Control groups involved direct saline (4.5 mL) clot injection in 0.5-1.0-mL increments. One group underwent peripheral intravenous microbubble injection (13.5 mL). Six groups underwent direct incremental clot injection of 4.5 mL of microspheres with LFUS for 30 minutes in 3-5-minute increments with use of various intensity settings in continuous-wave and pulsed-wave (PW) modes. At each increment, angiography was used to grade flow, declotting, and overall success. RESULTS One hundred four procedures showed success in all 24 high-intensity PW modes (1.2-2.0 W/cm(2)); only one of 20 control experiments was successful (P <.0001). Medium-intensity modes yielded intermediate success rates. Lowest-intensity direct-injection groups and intravenous and control groups ranked lower. Results at 30 minutes were better than at 15 minutes (P <.0001). CONCLUSIONS LFUS with direct injection of microbubbles is effective in lysing moderate-sized clots and recanalizing thrombosed arteriovenous grafts. It best succeeds at the higher range of intensity settings tested in PW mode. Further development is justified.

Hyperhomocysteinemia increases intimal hyperplasia in a rat carotid endarterectomy model

PURPOSE This preliminary study investigated the ability to elevate the serum homocysteine (H[e]) levels and investigated the increases in postoperative neointimal hyperplasia (IH) in an environment with hyperhomocysteinemia and the resultant restenosis in a rat carotid endarterectomy (CEA) model. METHOD The 9 rats for the control group were fed rat chow, and the 8 rats for the H(e) group were fed H(e)-supplemented rat chow for 2 weeks before and after CEA. The animals underwent anesthesia, and a left common CEA was performed. After 14 days, the serum H(e) levels were measured and the left carotid artery was harvested and elastin stained. Morphometric measurements were used to calculate the area of stenosis of the lumen. The mean and the standard deviation of the mean were determined. The 2 groups were compared with the Mann-Whitney test and a linear regression model. Three additional rats per group were studied, with carotid artery sectioning with double immunohistochemical staining for 5-bromodeoxyuridine (BrdU) and alpha-smooth muscle (alpha-SM) actin. RESULTS The serum H(e) level in the H(e) group was 36.32 micromol/L +/- 15.28, and in the control group the level was 5.53 micromol/L +/- 2.06 (P =.0007). IH presented as percent lumen stenosis was 21.89% +/- 4.82% in the H(e) group and 4.82% +/- 1.64% in the control group (P =.0007). The linear regression model of the serum H(e) levels and the percent stenosis showed a linear relationship (r2 =.72). The alpha-SM actin staining revealed that nearly all of the cells in the IH area were of smooth muscle or myofibroblast origin and that 10.1% +/- 2.6% of the cells were stained for BrdU in the control group versus 23% +/- 7.1% in the H(e) group. Also, 9.3% +/- 2.6% of the cells in the IH area were stained for BrdU and for alpha-SM actin versus 19.1% +/- 5. 6% stained for both BrdU and alpha-SM actin in the H(e) group. CONCLUSION This is the first study to examine IH after CEA and hyperhomocysteinemia in rats. The study shows that the elevation of serum H(e) levels can be obtained by feeding rats modified diets with added H(e). The consistent elevation of serum H(e) levels was associated with more than 4 times the amount of IH after a CEA in a rat model.

Abdominal Aortic Aneurysm Repair

Newer, minimally invasive catheter-based endovascular technology utilizing stent grafts are currently being evaluated for abdominal aortic aneurysm (AAA) repair. A retrospective review of all (3 years) consecutive, non-ruptured elective AAA repairs was undertaken to document the results of AAA surgical repair in a modern cohort of patients to allow a contemporary comparison with the evolving endoluminal data. One hundred twenty-one AAAs were identified in a male veteran population. Mean age was 68.5 ±7.7 years. Medical history review showed hypertension in 55%, heart disease in 73.5%, peripheral vascular disease in 21%, stroke and transient ischemic attacks in 22%, diabetes mellitus in 7%, renal insufficiency in 10%, and smoking history in 80%. The AAA size was documented with ultrasound (5.2 +1.3 cm, n = 40) and computed tomography (5.6 +1.3 cm, n= 100). Fifty-nine percent had angiography. Intraoperative end points included an operative time of 165 ±6.3 minutes from incision to dressing placement. A Dacron tube graft was used in 78%, the remaining were Dacron bifurcated grafts. A suprarenal clamp was used in 8% for proximal aortic control with juxtarenal aneurysms. A pulmonary-artery catheter was placed in 69%. A transverse incision was used in 69% of patients and a midline incision was used in the rest. Estimated blood loss was 1505 +103 mL; cell saver blood returned 754 +53 mL; crystalloid/Hespan 4771 ±176 mL; banked packed red blood cells 0.75 ±0.1 1 U. Time to extubation was, in the operating room (78.5%), on the day of the operation (5.0%), postoperative day (POD) 1 (12.4%), POD2 (1.7%), POD3 (0.8%), and one case was performed with epidural anesthesia only. Postoperative end points included a 30-day mortality rate of 1.6% (two patients). Postoperative morbidity included wound dehiscence 0.8%; sepsis, urinary tract infection, wound infection, leg ischemia, ischemic colitis, and stroke each had an incidence of 1.6%; myocardial infarction, congestive heart failure, pneumonia, re-operation for suspected bleeding, and ileus or bowel obstruction occurred with an incidence of 3.3%. No significant increase in serum creatinine levels was noted. Time to enteral fluids/nutrition was 3.5 +0.08 days. Patients were out of bed to a chair or walking by 1.3 +0.06 days postoperatively. The length of stay in the intensive care unit (ICU) was 2.0 +0.12 days and postoperative hospital stay was 6.6 + 0.33 days. Transfusion requirement for the hospital stay was 1.6 +0.2 U per patient. This review highlights a cohort of male veteran patients with significant cardiac co-morbidity who have undergone repair with a conventional open technique and low mortality and morbidity rates. This group had rapid extubation, time to oral intake, and ambulation. In addition, ICU and hospital stays were relatively short.

Infectious complications resulting from use of hemostatic puncture closure devices

BACKGROUND Femoral access site complications have increased as the fields of invasive cardiology, radiology, and endovascular surgery have emerged. In order to address one of these complications, hemorrhage, the hemostatic puncture closure devices were developed. METHODS Retrospective review of cardiac catheterizations performed at a single institution to investigate infectious groin complications related to use of the Perclose Prostar and Techstar devices. RESULTS Infectious groin complications were significantly higher in the Perclose group as compared with manual compression. Three patients had clinical and laboratory evidence of arterial infection whereas 2 had soft tissue infections. All 5 required operative intervention ranging from incision and drainage to arterial reconstruction. Hemorrhagic complications were not significantly different between the two groups. CONCLUSIONS The Perclose devices provide hemostasis after femoral artery catheterization similar to manual compression. However, infectious groin complications appear to be more common with these devices.

Blue Toe Syndrome: Treatment with Intra-arterial Stents and Review of Therapies

PURPOSE To determine if intra-arterial stent placement can adequately treat lesions producing microemboli to the lower extremities. MATERIALS AND METHODS During a 6.5-year period, 15 patients presenting with blue toe syndrome had 16 presumed embolic lesions treated with intra-arterial stents. These patients were evaluated during routine clinical follow-up during a 6-month period. This evaluation included physical and noninvasive arterial examinations. When patients could not return for follow-up, hospital, clinical, vascular laboratory, and radiology records were reviewed to assemble the appropriate information. Outcomes included symptoms of recurrent emboli, amputation, and death. RESULTS Treated embolic lesions included two aortic stenoses, three bilateral iliac artery stenoses, nine unilateral iliac artery stenoses (one patient received separate treatment of unilateral iliac lesions), and two superficial femoral artery stenoses. Patients were followed-up for a mean of 18 months. Eight of 15 patients (53%) were improved or stable without complications. There were eight negative outcomes experienced in seven patients. Three patients (20%) were deceased at follow-up. Four patients (27%) had undergone amputation; one transmetatarsal amputation and three below-the-knee amputations. Only one of these was related to progressive disease in the treated extremity (7%). One patient (7%) experienced recurrent embolic symptoms. Stents were patent in all patients. CONCLUSION Patients with blue toe syndrome are at high risk of limb loss and mortality despite treatment. Intra-arterial stent placement provides an alternative to standard surgical treatment. Further studies are needed to define the optimum therapy.

Assessment of apparent vena caval penetration by the Greenfield filter.

Purpose:To examine and elucidate the mechanisms for apparent “penetration” by Greenfield vena caval filters.Methods:Two filters were placed in the inferior venae cavae (IVC) of four immature sheep ...

Outcome-based anatomic criteria for defining the hostile aortic neck

OBJECTIVE There is abundant evidence linking hostile proximal aortic neck anatomy to poor outcome after endovascular aortic aneurysm repair (EVAR), yet the definition of hostile anatomy varies from study to study. This current analysis was undertaken to identify anatomic criteria that are most predictive of success or failure at the aortic neck after EVAR. METHODS The study group comprised 221 patients in the Aneurysm Treatment using the Heli-FX Aortic Securement System Global Registry (ANCHOR) clinical trial, a population enriched with patients with challenging aortic neck anatomy and failure of sealing. Imaging protocols were not protocol specified but were performed according to the institutions standard of care. Core laboratory analysis assessed the three-dimensional centerline-reformatted computed tomography scans. Failure at the aortic neck was defined by type Ia endoleak occurring at the time of the initial endograft implantation or during follow-up. Receiver operating characteristic curve analysis was used to assess the value of each anatomic measure in the classification of aortic neck success and failure and to identify optimal thresholds of discrimination. Binary logistic regression was performed after excluding highly intercorrelated variables, creating a final model with significant predictors of outcome after EVAR. RESULTS Among the 221 patients, 121 (54.8%) remained free of type Ia endoleak and 100 (45.2%) did not. Type Ia endoleaks presented immediately after endograft deployment in 58 (58.0%) or during follow-up in 42 (42.0%). Receiver operating characteristic curve analysis identified 12 variables where the classification of patients with type Ia endoleak was significantly more accurate than chance alone. Increased aortic neck diameter at the lowest renal artery (P = .013) and at 5 mm (P = .008), 10 mm (P = .008), and 15 mm (P = .010) distally; aneurysm sac diameter (P = .001), common iliac artery diameters (right, P = .012; left, P = .032), and a conical (P = .049) neck configuration were predictive of endoleak. By contrast, increased aortic neck length (P = .050), a funnel-shaped aortic neck (P = .036), and neck mural thrombus content, as measured by average thickness (P = .044) or degrees of circumferential coverage (P = .029), were protective against endoleak. Binary logistic regression identified three variables independently predictive of type Ia endoleak. Neck diameter at the lowest renal artery (P = .002, cutpoint 26 mm) and neck length (P = .017, cutpoint 17 mm) were associated with endoleak, whereas some mural neck thrombus content was protective (P = .001, cutpoint 11° of circumferential coverage). CONCLUSIONS A limited number of independent anatomic variables are predictive of type Ia endoleak after EVAR, including aortic neck diameter and aortic neck length, whereas mural thrombus in the neck is protective. This study suggests that anatomic measures with identifiable threshold cutpoints should be considered when defining the hostile aortic neck and assessing the risk of complications after EVAR.

Homocysteine-induced vascular dysregulation is mediated by the NMDA receptor

Elevated plasma homocysteine accelerates myointimal hyperplasia and luminal narrowing after carotid endarterectomy. N-methyl D aspartate receptors (NMDAr) in rat cerebrovascular cells are involved in homocysteine uptake and receptor-mediated stimulation. In the vasculature, NMDAr subunits (NR1, 2A-2D) have been identified by sequence homology in rat aortic endothelial cells. Exposure of these cells to homocysteine increased expression of receptor subunits, an effect that was attenuated by dizocilpine (MK801), a noncompetitive NMDA inhibitor. The objective of this study was to investigate the existence of an NMDAr in rat vascular smooth muscle (A7r5) cells, and also the effect of homocysteine on vascular dysregulation as mediated by this receptor. Subunits of the NMDAr (NR1, 2A-2D) were detected in the A7r5 cells by using the reverse transcriptase polymerase chain reaction and Western blotting. Homocysteine induced an increase in A7r5 cell proliferation, which was blocked by MK801. Homocysteine, in a dose and time dependent manner, increased expression of matrix metallinoproteinase-9 and interleukin-1beta, which have been implicated in vascular smooth muscle cell migration and/or proliferation. Homocysteine reduced the vascular elaboration of nitric oxide and increased the elaboration of the nitric oxide synthase inhibitor, asymmetric dimethylarginine. All of these homocysteine mediated effects were inhibited by MK801. NMDAr exist in vascular smooth muscle cells and appear to mediate, at least in part, homocysteine-induced dysregulation of vascular smooth muscle cell functions.