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Biomedical subjects

H J Safi

Publications and source records attributed to H J Safi.

At least 19 recordsLinked to original sources
PubMed2000

Surgical management of primary aortoesophageal fistula secondary to thoracic aneurysm.

Aortoesophageal fistula, secondary to thoracic aortic aneurysm, is an uncommon cause of gastrointestinal bleeding that is uniformly fatal without surgical intervention. These may be primary fistulas, in cases of thoracic aortic aneurysm without previous repair, or secondary fistulas occurring after surgical repair of thoracic aortic aneurysm. Surgical treatment has been successful in a small number of cases of primary aortoesophageal fistula, secondary to thoracic aortic aneurysm, but techniques used have varied. We report a successful repair of primary aortoesophageal fistula, secondary to descending thoracic aortic aneurysm, and review the evolution of management since the three previously reported successful repairs at our institution.

Aorta, Thoracic↗
PubMed2000

Reversal of twice-delayed neurologic deficits with cerebrospinal fluid drainage after thoracoabdominal aneurysm repair: a case report and plea for a national database collection.

Delayed neurologic deficits are an uncommon yet devastating complication of thoracoabdominal aortic aneurysm repair. The mechanisms involved in the development of delayed spinal cord ischemia remain ill defined. We report a case of complete reversal of delayed neurologic deficits with postoperative cerebrospinal fluid (CSF) drainage. After a thoracoabdominal aneurysm extent I repair, the patient experienced delayed paraplegia at 6 hours and again at 34 hours after the operation, with elevated CSF pressure (>10 mm Hg) on both occasions. Prompt CSF decompression completely reversed the neurologic deficits within hours after onset. The findings in this case further support the role of CSF drainage in spinal cord protection for patients who undergo thoracoabdominal aneurysm repair and make a plea for a national database collection.

Aged↗
PubMed1999

Reduction of lipid peroxidation with intraoperative superoxide dismutase treatment decreases intimal hyperplasia in experimental vein grafts.

BACKGROUND: Vein graft failure is commonly attributed to the development of intimal hyperplastic lesions. Oxidative stress has been implicated in the initiation and progression of atherosclerosis. In this study we examined the effects of local intraoperative treatment with polyethylene glycolated superoxide dismutase (PEG-SOD) on lipid peroxidation and on the development of intimal hyperplasia in experimental vein grafts. MATERIALS AND METHODS: Forty-one New Zealand White male rabbits had a right carotid interposition bypass graft using the ipsilateral reversed jugular vein. Sixteen animals received local PEG-SOD (4,100 units) treatment; 9 animals received the polyethylene glycol (PEG) vehicle without SOD; 16 animals were used as controls. Postoperatively, malondialdehyde (MDA, a product of lipid peroxidation) concentration and SOD activity were assessed in 3-day vein grafts by colorimetric spectrophotometry. To determine wall dimensions and vasomotor function, morphometric and isometric tension studies were performed on 28-day vein grafts. RESULTS: MDA concentration was increased 5. 7-fold (P < 0.05) in 3-day control vein grafts compared to ungrafted jugular veins. Intraoperative PEG-SOD treatment raised SOD activity 5.0-fold (P < 0.05) and reduced MDA concentration 8-fold (P < 0.05) in 3-day vein grafts compared to controls. At 28 days, intimal thickness was reduced by 35% with PEG-SOD treatment (54 +/- 4 vs 83 +/- 5; P < 0.001) compared to control vein grafts, without a change in medial thickness (77 +/- 4 vs 88 +/- 5; P = ns). The vasomotor functions of 28-day PEG-SOD-treated vein grafts to norepinephrine, serotonin, bradykinin, nitroprusside, and acetylcholine were not significantly changed when compared to controls. Treatment with PEG alone did not significantly alter lipid peroxidation, wall dimensions, or vasomotor function of vein grafts. CONCLUSION: This study demonstrates that intraoperative local treatment of vein grafts with PEG-SOD increases SOD activity and decreases lipid peroxidation for at least 3 days, resulting in reduced intimal hyperplasia at 28 days. These findings further implicate oxidative stress in the hyperplastic response of vein grafts and suggest a potential therapeutic role for PEG-SOD in the prevention of vein graft failure.

Animals↗
PubMed1999

Progress in the management of type I thoracoabdominal and descending thoracic aortic aneurysms.

We reviewed our categorization of patients at high risk for neurologic complications in the repair of descending thoracic and thoracoabdominal aortic aneurysm in which we used cerebrospinal fluid drainage and distal aortic perfusion (adjuncts). A total of 409 patients were operated on by one surgeon for descending thoracic or thoracoabdominal aortic aneurysm between 1992 and 1997. Of these patients, 232 had total descending thoracic or type I thoracoabdominal aortic aneurysm, 131 (56%) of whom were operated on with adjuncts. These patients were compared to 101 nonadjunct patients for demographic variables, intraoperative variables, blood product consumption, and neurologic status. In 131 consecutive patients with adjuncts, all but one awoke from anesthesia without neurologic deficit. In nonadjunct patients, however, neurologic deficit occurred in 6 of 101 (6%) (p < 0.003). The adjunct group had more preoperative renal insufficiency (p < 0.05), an established risk factor for neurologic deficit (odds ratio = 2.2 in published studies). All other risk factors for neurologic deficit occurred with comparable frequency in both groups. We conclude that the introduction of adjuncts has dramatically reduced the neurologic risk associated with type I thoracoabdominal or total descending thoracic aortic repair. Previously considered high risk for neurologic complications, these aneurysms can now be reclassified as low risk in surgery accompanied by adjuncts. Future investigations will focus on type II thoracoabdominal aortic aneurysm as the major source of neurologic morbidity.

Adolescent↗
PubMed1999

The anatomical aspects of minimally invasive cardiac valve operations.

Cadaveric dissections were carried out to examine the relationship of the cardiac valve structures to the surface anatomy of the chest as it relates to our approaches to minimally invasive valvular operations. The techniques of upper hemisternotomy and lower hemisternotomy as used at our institution are described.

Cardiac Surgical Procedures↗
PubMed1999

Spinal cord protection in descending thoracic and thoracoabdominal aortic repair.

BACKGROUND: During simple cross-clamp repair of the descending thoracic or thoracoabdominal aorta, the likelihood of neurologic complications increases greatly after only 30 minutes of spinal cord ischemia. At greatest risk are patients with type II thoracoabdominal aortic aneurysms. METHODS: We reviewed our experience of simple cross-clamp repair and procedures accompanied by adjuncts, paying particular attention to the outcome of patients who had type II thoracoabdominal aortic aneurysms. Between February 1991 and March 1998, 508 patients had descending thoracic and thoracoabdominal aortic repair, 255 (50.2%) of whom received the adjuncts of cerebrospinal fluid drainage and distal aortic perfusion. RESULTS: Fifteen patients died on the day of operation and could not be evaluated for neurologic deficit. The overall incidence of neurologic deficit was 33 of 493 patients (6.7%). In patients who received adjuncts, neurologic deficit occurred in 9 of 247 (3.6%) overall; in types I and II it was 8 of 164 (4.9%), and in type II alone, 7 of 87 (8.1%). Neurologic deficit in simple cross-clamp patients was 24 of 246 (9.8%) overall; in types I and II it was 15 of 99 (15.2%), and in type II alone, 13 of 44 (29.6%). CONCLUSIONS: With the surgical adjuncts of cerebrospinal fluid drainage and distal aortic perfusion, the probability of neurologic deficit is lowered appreciably.

Adolescent↗
PubMed1999

Pharmacokinetics of liposomal aerosolized cyclosporine A for pulmonary immunosuppression.

BACKGROUND: The results of pulmonary transplantation are compromised by acute and chronic rejection. We hypothesized that a liposomal form of aerosolized cyclosporine A (CsA) would be selectively deposited and concentrated in the lungs. The theoretical advantage of this therapy is selective pulmonary immunosuppression with prolonged utilization. METHODS: Eighteen dogs were endotracheally intubated; aerosolized liposomal CsA was administered for 15 min. CsA levels were measured in whole blood, lung, trachea, heart, kidney, liver, and spleen at various times after treatment. RESULTS: The lung rapidly absorbs aerosolized liposomal CsA; other organs have much lower concentrations. The retention of pulmonary CsA delivered by liposome aerosol is approximately 120 min in this model. CONCLUSIONS: Aerosolized liposomal CsA is selectively deposited and concentrated in the lungs; other organs absorb less CsA.

Aerosols↗
PubMed1999

The impact of diaphragm management on prolonged ventilator support after thoracoabdominal aortic repair.

PURPOSE: The relationship of the division of the diaphragm during thoracoabdominal aortic repair to prolonged ventilator support has not been studied. The purpose of this study was (1) to determine whether preservation of diaphragm integrity has a significant effect on postoperative ventilator duration and (2) to elucidate other pulmonary risk factors related to thoracoabdominal aortic surgery and to study the relationship of these factors to the intact diaphragm technique. METHODS: Between February 1991 and January 1997, we repaired 397 descending and thoracoabdominal aortic aneurysms. Descending thoracic aneurysms were not included in the study because their repair does not include the diaphragm. A total of 256 patients participated in this study. The diaphragm was divided in 150 patients and left intact in 106 patients. Examined as potential risk factors were patient demographics, history and physical findings, aneurysm extent, urgency of the procedure, acute dissection, cross-clamp time, homologous and autologous blood product consumption, and adjunctive operative techniques. FEV1 also was considered in the 197 patients for whom preoperative spirometry was available. Prolonged mechanical ventilation was defined as ventilator support for >72 hours. Data were analyzed by univariate contingency table and multiple logistic regression methods. RESULTS: Increasing age (odds ratio [OR], 1.02/y; P <.02), current smoking (OR, 2.6; P <.0008), total cross-clamp time (OR, 1.0/min; P <.008), units packed red blood cells transfused (OR, 1.06/unit; P <.008), and division of the diaphragm (OR, 2.03; P <.02) were significant, independent predictors of prolonged ventilation. Sixty-seven percent of patients (71 of 106) whose diaphragms were preserved were extubated in <72 hours compared with 52% of patients (78 of 150) who underwent diaphragm division (OR, 0.53; P <.02). CONCLUSION: Independently of well known pulmonary risk factors, an intact diaphragm during thoracoabdominal aortic repair results in a higher probability of early ventilator weaning.

Adolescent↗
PubMed1999

How I do it: thoracoabdominal aortic aneurysm graft replacement.

A technique of aortic graft replacement in thoracoabdominal aortic aneurysm repair is described. The author's experience with the surgical adjuncts of cerebrospinal fluid drainage and distal aortic perfusion, and the evolution and rationale of thoracoabdominal aortic aneurysm classification are discussed. Interpretation of the large amount of data that the author has accumulated would have been impossible without such a system.

Aortic Aneurysm, Abdominal↗
PubMed1999

Actual versus actuarial analysis for cardiac valve complications: the problem of competing risks.

Methods for analyzing rates of events such as heart valve failure following surgery are important for comparing different techniques and devices; however, in patients undergoing major surgery, other risks such as mortality compete with the risk of heart valve failure to determine each patient's final outcome. When multiple, mutually exclusive endpoints are possible, a situation known to statisticians as a competing risks problem arises. No single statistical technique that is currently available provides an entirely satisfactory solution to this problem. We argue that in order for valve failure incidences to be useful clinically, the overall patient outcome milieu from which these failures arise must be considered. In this article, we review recent work in the area of competing-risks analysis as it pertains to heart valve surgery outcome.

Actuarial Analysis↗
PubMed1999

External support modulates G protein expression and receptor coupling in experimental vein grafts.

BACKGROUND: Intimal hyperplasia remains the leading cause of vein graft failure. Various external stenting devices have been shown to reduce the development of intimal hyperplasia in vein grafts. Mitogenic and mechanotransduction signals are known to be mediated by G protein-coupled receptors. Therefore in this study we examined the alterations in G protein expression and receptor coupling in vein grafts stented with external tube support. METHODS: Thirty New Zealand White male rabbits had a right carotid interposition bypass graft with use of the ipsilateral jugular vein. Fifteen animals received external support and 15 were controls. In a subset the animals either had removal of the external support or a sham-control neck exploration at 14 days after the initial implantation (n = 5 per group). RESULTS: External support reduced G alpha i3 proteins by 30% in vein grafts without changes in G alpha s by Western blot. Vein grafts with external support were significantly less sensitive to pertussis toxin inactivation than controls were in response to both norepinephrine and serotonin. A 24% decrease in intimal thickness was maintained after withdrawal of the initial external support. CONCLUSIONS: The placement of an external support is associated with alternations in G protein expression and receptor coupling function in vein grafts. The results of this study suggest that the development of vein graft intimal hyperplasia may involve G protein-mediated events.

Animals↗
PubMed1999

Methods of acute postcardiotomy left ventricular assistance.

OBJECTIVE: Despite many technological advances in cardiovascular surgery, some patients still experience postcardiotomy left ventricular (LV) failure that is refractory to both inotropic support and intra-aortic balloon pump (IABP) placement. The primary author (MJR) recently changed from inflow cannulation at the right superior pulmonary vein/left atrial junction to inflow cannulation at the dome of the left atrium. The purpose of this study was to compare data collected during placement of a left ventricular assist device (LVAD) at the junction of the right superior pulmonary vein with positioning the device in the dome of the left atrium. Experimental design, setting, and participants: the medical records of all patients undergoing cardiac surgery by one author (MJR) between 1994 and 1997 were retrospectively reviewed, and 4 patients requiring LVAD placement for short term postcardiotomy support were identified. Each patient's chart was reviewed for duration of LVAD support, average LVAD blood flows, pulmonary capillary wedge pressures (PCWP), preoperative characteristics, postoperative complications, and final outcome for the patients. RESULTS: Accessing the left atrium through the dome resulted in excellent blood flow through the LVAD and allowed for good LV decompression. Hemostasis remained the most common complication regardless of the technique employed; however, the enhanced visibility provided by accessing the left atrium via the dome made repairs less technically difficult. Three patients (75%) were able to be weaned from the LVAD and were discharged from the hospital to home. Two of these patients were cannulated via the left atrial dome making removal of the LVAD easier, thus exposing the patients to less additional operative time. One patient could not be weaned from LVAD support secondary to development of right ventricular failure requiring RVAD insertion and subsequent development of multiple organ failure syndrome. CONCLUSIONS: Patients requiring LV assistance following cardiopulmonary bypass surgery traditionally have high levels of morbidity and mortality. In spite of the complications associated with the placement of an assist device, we remain encouraged by the excellent LV decompression and systemic flows we achieved following implantation of the LVAD through the dome of the left atrium. The superior ease of implantation and decannulation provided better operative care and postoperative management for our patients.

Acute Disease↗
PubMed1998

Operation for acute and chronic aortic dissection: recent outcome with regard to neurologic deficit and early death.

BACKGROUND: We reviewed our experience in the repair of acute and chronic aortic dissection with regard to early neurologic deficit and death. METHODS: Between February 1991 and June 1996, we performed 206 operations on 195 patients for aortic dissection. Ascending or arch repair, or a combination (type A dissection) was performed on 92 of 206 patients (45%); 44 of 92 (48%) were acute dissection and 48 of 92 (52%) were chronic. Descending or thoracoabdominal repair (type B dissection) was performed on 114 of 206 patients (55%); 22 of 114 (19%) were acute and 92 of 114 (81%) were chronic. RESULTS: Among type A cases, strokes occurred in 6 of 92 patients (7%) overall; 4 of 44 (9%) were acute cases and 2 of 48 (4%) were chronic (p < 0.34). Early deaths for type A were 11 of 92 (12%) overall; 9 of 44 (20%) acute and 2 of 48 (4%) chronic (p < 0.02). In type B cases, neurologic complications were 15 of 114 (13%) overall; 7 of 22 (32%) were acute cases and 8 of 92 (9%) were chronic (p < 0.004). Early deaths for type B were 12 of 114 (11%) overall; 3 of 22 (14%) acute and 9 of 92 (10%) chronic (p < 0.6). Preoperative hypotension was significant in acute type A patients, with strokes in 2 of 7 (29%) hypotensives compared with 2 of 37 (5%) normotensives (p < 0.05) and early death in 4 of 7 (57%) hypotensives versus 5 of 37 (14%) normotensives (p < 0.009). CONCLUSIONS: Morbidity and mortality for repair of chronic dissection types A and B were acceptable. Preoperative hypotension in acute type A dissection was a major predisposing factor toward stroke (29% versus 5%, p < 0.05). Acute type B dissection had acceptable mortality (14%) but a high rate of neurologic complications (32%).

Acute Disease↗
PubMed1998

Effect of extended cross-clamp time during thoracoabdominal aortic aneurysm repair.

BACKGROUND: In previous studies of the neurologic outcome of patients undergoing thoracoabdominal aortic aneurysm repair with the simple cross-clamp technique, cross-clamp time of greater than 30 minutes was identified as an important risk factor. We retrospectively examined the effect of clamp time of 30 minutes or greater on outcome for patients undergoing repair with the addition of surgical adjuncts. METHODS: Between February 1991 and June 1996 we operated on 370 patients for thoracoabdominal or descending thoracic aortic aneurysm. Two hundred seventy-one of these patients with cross-clamp times of 30 minutes or greater were included in this study. One hundred twelve patients underwent simple cross-clamp repair, whereas 159 were operated on with the surgical adjuncts of distal aortic perfusion and cerebrospinal fluid drainage. RESULTS: By multivariate analysis, acute dissection, surgical adjuncts, and aneurysm extent proved most significant in overall patient outcome. The overall rate of early neurologic deficits was 23 of 271 (8.5%). For highest risk patients with type II thoracoabdominal aortic aneurysms, the rate of neurologic deficits was 11 of 29 (38%) for cross-clamp versus 6 of 82 (7.3%) for adjunct operation patients (odds ratio = 0.13; p < 0.001). CONCLUSIONS: The adjuncts of cerebrospinal fluid drainage and distal aortic perfusion decreased the risk of extended cross-clamp time during thoracoabdominal aortic aneurysm repair, particularly for highest risk type II.

Aged↗
PubMed1998

Management of the patient with aortic root disease and aortic insufficiency.

There is no single standardized method of repair for the anatomic variations in aortic root pathology, which may include dissection, aneurysmal dilation, and valve disease and can occur at the annulus, sinuses of Valsalva, or the sinotubular junction. Composite valve/graft replacement, valve resuspension, and allograft each play a significant role in aortic root therapy, but none is applicable in all cases. Patient age, Marfan's syndrome, endocarditis, and previous valve replacement are examples of some of the wide variations in delineating factors.

Aorta↗
PubMed1998

Thoracic and thoracoabdominal aortic aneurysm repair using cardiopulmonary bypass, profound hypothermia, and circulatory arrest via left side of the chest incision.

PURPOSE: Although some authors advocate hypothermic circulatory arrest for spinal cord protection in descending thoracic and thoracoabdominal repair, this method has been associated with high morbidity and mortality rates in other studies. The safety and effectiveness of this surgical adjunct were evaluated. METHODS: Between February 1991 and April 1997, 409 patients underwent thoracic or thoracoabdominal aortic repair. Because of an inability to gain proximal aortic control because of anatomic or technical difficulty, hypothermic circulatory arrest was used in 21 patients (4.9%). Thirteen patients were men, 8 were women, and the median age was 57 (range, 21 to 81 years). Four patients (19%) had Marfan's syndrome, and 1 had aortitis. Seven patients (33%) had aortic dissection (4 chronic type A, 2 chronic type B, 1 acute B), and 1 had aortic laceration. All but 6 patients had hypertension. Fifteen patients (73%) were operated on for repair of the distal arch and descending thoracic aorta, 4 (19%) for repair of the distal arch and thoracoabdominal aorta, and 2 for repair of either the thoracoabdominal or descending thoracic aorta alone. Surgery for 9 patients (43%) also included bypass grafts to the subclavian or innominate arteries. Six operations (29%) were urgent. RESULTS: The overall 30-day mortality rate was 29% (6 of 21 patients). Among urgent patients, the mortality rate was 50% (3 of 6 patients) versus 20% (3 of 15) for elective patients. Of the remaining 15 patients, renal failure occurred in 1 (7%) and heart failure in 2 (13%). Ten patients (67%) had pulmonary complications. Encephalopathy occurred in 5 patients (33%) and stroke in 2 (13%), and spinal cord neurologic deficit developed in 2 (13%). The median recovery was 28 days (range, 10 to 157 days). CONCLUSION: Hypothermic circulatory arrest did not reduce the incidence of deaths and morbidity to a rate comparable with our conventional methods. We recommend the judicious application of this method in rare instances when proximal control is not feasible or catastrophic intraoperative bleeding leave the surgeon with no other option.

Adult↗
PubMed1998

Importance of intercostal artery reattachment during thoracoabdominal aortic aneurysm repair.

PURPOSE: We studied the relationship of neurologic deficit to ligation, reimplantation, and preexisting occlusion of intercostal arteries to determine which arteries and consequent management are most critical to outcome in thoracoabdominal aortic aneurysm repair. METHODS: From February 1991 to July 1996, 343 patients with thoracoabdominal aortic aneurysms underwent repair by one surgeon. In this study, only Crawford types I, II, and III (n = 264) were considered. Of these, 110 (42%) were type I, 116 (44%) type II, and 38 (14%) type III. The adjuncts of distal aortic perfusion and cerebrospinal fluid drainage were used in 164 patients (62%). Data were analyzed by contingency table and by multiple logistic regression. RESULTS: Early neurologic deficit occurred in 23 patients (8.7%), and late deficit in 10 patients (3.8%). Neurologic deficit in patients with at least one reimplantation and no ligation of arteries T11 or T12 occurred in 19 of 147 (12.9%). Neurologic deficit for occlusion of the same arteries occurred in 11 of 111 (9.9%), whereas for ligation of T11 and T12 neurologic deficit occurred in three of six (50%; reimplantation, p < 0.03; occlusion, p < 0.006). In addition, reimplantation of intercostal arteries T9 or T10 was significantly associated with reduced late neurologic deficit in multivariate analysis (p = 0.05). No other intercostal artery status was associated with modification of the neurologic deficit rate. Multivariate analysis showed type II aneurysms and acute dissections to be significantly associated with an increased risk of postoperative neurologic deficit (p < 0.0009, 0.002, respectively). Adjuncts were protective (p < 0.007), most often in types II and III (14.1% neurologic deficit in type II with adjunct, 35.3% without; 0% in type III with adjunct, 20% without). CONCLUSION: Patients with patent arteries at the T11/T12 level have highly variable outcomes depending on whether the arteries are reattached or ligated. Our data suggest that reimplantation of thoracic intercostal arteries T11 and T12 is indicated when these arteries are patent. Reimplantation of T9 and T10 lowers the risk of late neurologic deficit, probably by decreasing the spinal cord's vulnerability to changes in blood and cerebrospinal fluid pressure in the days after surgery. Adjuncts lower overall risk and provide adequate time for targeted intercostal artery reimplantation.

Adolescent↗