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Biomedical subjects

H J Safi

Publications and source records attributed to H J Safi.

At least 37 records · Page 2Linked to original sources

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↗

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↗

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↗

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↗

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↗

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↗

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↗

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↗

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↗

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↗

Impact of distal aortic and visceral perfusion on liver function during thoracoabdominal and descending thoracic aortic repair.

PURPOSE: We examined the impact of distal aortic and visceral perfusion on liver function during thoracoabdominal and descending thoracic aortic repair. METHODS: Between January 1991 and July 1996, 367 patients underwent thoracoabdominal and descending thoracic aortic repair. Baseline and postoperative total bilirubin, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase, fibrinogen, prothrombin time (PT), and partial thromboplastin time (PTT) were measured for 286 patients. We examined the impact of distal aortic and direct visceral perfusion on liver function-related clinical laboratory values. Univariate and multivariate statistical methods for categorical and continuous variables were used. RESULTS: In categorical analysis, type II thoracoabdominal aortic aneurysm, history of hepatitis, and emergency presentation had a statistically significant multivariate association with abnormal laboratory values. In continuous-distributed multivariate data analysis, type II thoracoabdominal aortic aneurysm and visceral perfusion were statistically significant predictors of postoperative alkaline phosphatase, PT, and PTT. Type II aneurysms increased postoperative liver function-related laboratory values significantly above other aneurysm types (alkaline phosphatase, +114 IU, p < 0.0001; PT, +1.99 seconds, p < 0.02; PTT, +6.7 seconds, p < 0.03). Visceral perfusion was associated with a concomitant decrease (alkaline phosphatase, -101.2 IU, p < 0.0001; PT, -1.8 seconds, p < 0.07; PTT, -5.6 seconds, p < 0.02). CONCLUSIONS: Visceral perfusion negates the rise in postoperative liver function-related clinical laboratory values associated with type II thoracoabdominal aortic aneurysm repair.

Alkaline Phosphatase↗

Spinal cord protection in descending thoracic and thoracoabdominal aortic aneurysm repair.

During aneurysm repair of the descending thoracic or thoracoabdominal aorta, the likelihood of neurological complications increases greatly after only 30 minutes of spinal cord ischemia. However, the manifestation of paraplegia or paraparesis relates not only to aortic cross-clamping time, but to multiple factors that may include aortic dissection, previous aortic surgery, advanced age, preoperative renal insufficiency, rupture, and most significantly, aneurysm extent. At greatest risk is the patient with type II thoracoabdominal aortic aneurysm. For this patient the simple cross-clamp technique, which uses no protective surgical adjuncts, heightens the threat of neurological deficit. With the surgical adjuncts of cerebrospinal fluid drainage and distal aortic perfusion, the probability of neurological deficit is appreciably lowered.

Aortic Aneurysm, Abdominal↗

Aortic valve disease in Marfan syndrome.

The Marfan syndrome patient undergoes care by many different physicians for the treatment of the varied systems affected by this connective tissue disorder. The most frequent visits are to a cardiologist, with referral to a cardiovascular surgeon who attends to the problems of dilatation and dissection of the ascending aorta. Follow-up is lifelong. Although currently some surgeons prefer to resuspend rather than replace the aortic valve, composite valve graft replacement for aortic root dilatation and aortic valve insufficiency has steadily improved patient outcome. At the same time, the almost daily discoveries of genetic science show great promise in eliminating connective tissue disorders such as Marfan syndrome in the not-too-distant future.

Aortic Valve↗

Mitral valve injury from blunt trauma.

Mitral valve injury from blunt trauma to the chest is an uncommon entity. We report a case of mitral valve injury after a fall, and its repair. The English literature is reviewed from the earliest report in 1873 to the present. The diagnosis, types of injury and surgical correction are discussed.

Accidental Falls↗

Impact of retrograde cerebral perfusion on ascending aortic and arch aneurysm repair.

PURPOSE: The effect of retrograde cerebral perfusion on the incidence of stroke and death among patients undergoing repair of aneurysms of the ascending aorta and transverse arch was determined. MATERIALS AND METHODS: Between January 1991 and March 1995, 161 patients were operated on for aneurysms of the ascending aorta and transverse arch. Thirty-three of the patients (20%) had an aneurysm of the ascending aorta only and 128 (80%) had aneurysms of both the ascending aorta and the transverse arch. All the patients underwent cardiopulmonary bypass, profound hypothermia, and circulatory arrest, and 120 (74%) also underwent retrograde cerebral perfusion. Median pump time was 143 minutes (range, 21 to 461 minutes). Median circulatory arrest time was 42 minutes (range, 8 to 111 minutes), and median myocardial ischemic time was 71 minutes (range, 14 to 306 minutes). RESULTS: The overall 30-day mortality rate was 6% (9 patients) and the incidence of stroke was 4% (7 patients). The use of retrograde cerebral perfusion demonstrated a protective effect against stroke (3 of 120 patients, or 3%) compared with no retrograde cerebral perfusion (4 of 41 patients, or 9%; odds ratio, 0.24; confidence interval, 0.06 to 0.99; p < 0.049). This was most significant in patients more than 70 years of age; none of the 36 elderly patients who received retrograde cerebral perfusion had a stroke, compared with 3 of the 13 (23%) who did not (p < 0.003). Only pump time was associated with an increased risk of stroke (odds ratio, 1.01; 95% confidence interval, 1.00 to 1.02; p < 0.005). Pump time also was associated with increased mortality (odds ratio, 1.01; 95% confidence interval, 1.00 to 1.02; p < 0.008). CONCLUSION: Retrograde cerebral perfusion decreased the incidence of stroke in patients undergoing repair of aneurysms of the ascending aorta and transverse arch.

Adult↗

Ischemic left ventricular free wall rupture: prediction, diagnosis, and treatment.

Left ventricular free wall rupture is the third leading complication and the second most common cause of death after myocardial infarction. Its occurrence has been considered an unpredictable event usually leading to death. An increased appreciation for the clinical presentation of this syndrome and the nearly ubiquitous use of echocardiography have fostered a rise in the antemortem diagnosis of left ventricular free wall rupture, allowing the possibility of operative repair. Despite the increased reporting of left ventricular free wall rupture, the experience of any one surgeon or surgical group tends to be quite small. We review the current status of rupture prediction, clinical presentation, diagnosis, and treatment options. A recent case of left ventricular free wall rupture referred to the Baylor Cardiothoracic Surgery Group with the misdiagnosis of ruptured dissection of the ascending thoracic aorta is presented to illustrate our approach to this clinical situation.

Heart Rupture, Post-Infarction↗

CT reconstruction of an unusual chronic posttraumatic aneurysm of the thoracic aorta.

Chronic traumatic aneurysm of the thoracic aorta is an unusual occurrence. Previously, arteriography was performed on all patients seen in our institution with this entity to allow confirmation of the diagnosis and anatomic delineation for operation. A case of chronic traumatic aneurysm of the distal descending aorta discovered on a routine chest roentgenogram and evaluated with chest computed tomographic scanning with three-dimensional reconstruction is presented. It is our belief that not all thoracic aneurysms require arteriography, and improved methods of computed tomographic scanning allow adequate diagnosis and anatomic delineation with decreased morbidity and cost.

Accidents, Traffic↗