Biomedical subjects

David Spielvogel

Publications and source records attributed to David Spielvogel.

36 records · Page 2Linked to original sources

PubMed2003

Cerebral physiology and outcome after hypothermic circulatory arrest followed by selective cerebral perfusion.

BACKGROUND: This study explored the impact of an interval of hypothermic circulatory arrest (HCA) preceding selective cerebral perfusion (SCP) on cerebral physiology and outcome. This protocol allows use of SCP during aortic surgery without the threat of embolization inherent in balloon catheterization of often severely atherosclerotic cerebral vessels. METHODS: In this blinded study, 30 pigs (20 to 22 kg) were randomized after cooling to 20 degrees C. Pigs in the HCA-CPB group (n = 10) underwent 30 minutes of HCA followed by 60 minutes of total body perfusion (CPB); HCA-SCP pigs (n = 10) underwent 30 minutes of HCA followed by 60 minutes of SCP, and SCP pigs (n = 10) had 90 minutes of SCP without prior HCA. Fluorescent microspheres enabled calculation of cerebral blood flow during perfusion and recovery. Hemodynamics, intracranial pressure, cerebrovascular resistance, and cerebral oxygen consumption were also monitored. Daily behavioral scores were obtained for 7 days postoperatively. RESULTS: In all groups, cerebral oxygen consumption fell significantly with cooling (p < 0.0001), remained low during perfusion, and rebounded promptly with rewarming; cerebral oxygen consumption was significantly (p = 0.027) greater during SCP than during HCA-CPB. Cerebral blood flow was significantly higher throughout SCP in the HCA-SCP group (p < 0.0001) than with CPB. Cerebrovascular resistance during SCP and HCA-SCP was significantly lower (p = 0.036) than during CPB. Behavioral scores were significantly better with SCP than with HCA-CPB throughout recovery, but did not differ between SCP and HCA-SCP. CONCLUSIONS: This study suggests that a short period of HCA preceding SCP provides global cerebral protection comparable to continuous SCP, implying that in clinical practice, a short period of HCA to reduce risk of embolization will not compromise the superior cerebral protection provided by SCP.

Animals↗

PubMed2003

Aortic arch reconstruction using a trifurcated graft.

Cerebral protection and prevention of atheroembolism remain challenges in aortic arch reconstruction. To reduce neurologic complications, we developed a "no-touch" technique in which a trifurcated graft is anastomosed to the arch vessels during hypothermic circulatory arrest, reducing the risk of embolization while minimizing cerebral ischemia by permitting antegrade cerebral perfusion as arch reconstruction is completed.

Anastomosis, Surgical↗

PubMed2003

Is the Bentall procedure for ascending aorta or aortic valve replacement the best approach for long-term event-free survival?

BACKGROUND: This retrospective analysis of a selected series of Bentall procedures may be useful in evaluating the results of valve-sparing operations, an increasingly popular alternative for replacement of the ascending aorta and aortic valve. METHODS: One hundred forty-two elective patients younger than 65 years without concomitant procedures who underwent replacement of the thoracic aorta and aortic valve between 1989 and 2000 were studied; 85% were men, and the median age was 46 years (range, 13 to 64 years). Degenerative disease of the aorta was the most common cause requiring operation (86%, including 46% with a bicuspid aortic valve); 8% had chronic dissection, and 6% had atherosclerotic aneurysms. The ascending aorta was replaced in 94 patients (66%); 45 patients (32%) underwent hemiarch replacement, and in 3 patients (2%) the total arch was replaced. A mechanical valve was used in 88%, and a biologic valve, in 12%. RESULTS: There were no intraoperative deaths. Two patients had a stroke postoperatively, one of which was fatal. Complications during follow-up included 2 cases of endocarditis, 1 peripheral thromboembolic event, and 10 instances of significant bleeding (requiring hospitalization or transfusion). Surgery for distal aortic segments was performed in 4 patients, but no patient required reoperation in the proximal aorta. Kaplan-Meier curves show overall survival is 0.95 (95% confidence intervals, 0.9 to 0.99) at 5 years and 0.93 (95% confidence intervals, 0.86 to 0.99) at 8 years, and event-free survival is 0.85 (95% confidence intervals, 0.78 to 0.92) at 5 years and 0.78 (95% confidence intervals, 0.68 to 0.88) at 8 years. CONCLUSIONS: The button Bentall procedure can be performed with excellent short-term and long-term results in relatively uncomplicated elective patients in whom aortic valve disease is combined with dilatation of the ascending aorta. Results of this traditional operation are the standard against which the long-term outcome of newer approaches, such as valve-sparing operations, should be compared.

Adolescent↗

PubMed2003

Diabetes and evidence of atherosclerosis are major risk factors for adverse outcome after elective thoracic aortic surgery.

BACKGROUND: To predict risk after elective repair of ascending aorta and aortic arch aneurysms, we studied 464 consecutive patients. METHODS: Adverse outcome (stroke or hospital death) was analyzed in 372 patients who underwent proximal repair and 92 patients who underwent aortic arch replacement from 1986 to the present. Preoperative risk factors with a P value less than.2 in a univariate analysis were entered into a multivariate model, and an equation incorporating independent risk factors was derived separately for proximal aorta and arch surgery. RESULTS: Age more than 65 years (P =.04), diabetes (P =.02), cause (P =.01), and prolonged total cerebral protection time (duration of hypothermic circulatory arrest and selective cerebral perfusion, P =.001) were significant univariate risk factors for elective proximal aortic repair. Diabetes (P =.005, odds ratio 5.1), atherosclerosis (P =.003, odds ratio 4.0), and dissection (P =.048, odds ratio 2.5) were independent factors. For elective arch surgery, female sex (P =.07), age more than 65 years (P =.04), coronary artery disease (P =.02), diabetes (P =.06), cause (P =.07), and prolonged total cerebral protection time (P =.025) were univariate risk factors. Female sex (P =.05, odds ratio 4.7), coronary artery disease (P =.02, odds ratio 6.5), diabetes (P =.13, odds ratio 4.0), and total cerebral protection time (P =.03, odds ratio 1.02/min) were independent factors. To calculate risk of adverse outcome (P), enter 1 if factor is present, 0 if absent, and estimate total cerebral protection time (in minutes). [equation: see text]. CONCLUSION: In this large series of patients, the presence of diabetes and manifestations of atherosclerosis emerge as extremely important risk factors for adverse outcome after ascending aorta or arch surgery, displacing age. Multivariate equations derived from these data allow more precise calculation of risk for each individual contemplating elective surgery.

Adolescent↗

PubMed2003

Challenges of endovascular tube graft repair of thoracic aortic aneurysm: midterm follow-up and lessons learned.

OBJECTIVES: Endovascular stent-graft repair has great potential in treatment of thoracic aortic aneurysms. This study analyzed a single center's experience with first-generation commercially produced thoracic stent grafts used to treat descending thoracic aortic aneurysms. METHODS: Over 58 months 84 patients underwent endovascular stent-graft repair of descending thoracic aortic aneurysms; 22 patients received the Gore TAG stent graft, and 62 patients received the Talent thoracic endovascular stent-graft system. Each patient was enrolled in one of three distinct US Food and Drug Administration trials at Mount Sinai Medical Center in accordance with strict inclusion and exclusion criteria, including suitability for open surgery, aneurysm anatomy, and presence of comorbid medical illness. Mean age of this cohort was 71 +/- 12 years. There were 54 men and 30 women, and 74 (88%) had three or more comorbid illnesses. Primary technical success was achieved in 76 patients (90%). Mean follow-up was 15 months (range, 0-52 months). RESULTS: Successful aneurysm exclusion was achieved in 69 patients (82%). Major procedure-related or device-related complications occurred in 32 patients (38%). There were six proximal attachment failures (8%), four distal attachment failures (6%), one intergraft failure (1%), two mechanical device failures (3%), five periprocedural deaths (6%), and five late aneurysm ruptures (6%). At 40 months, overall survival was 67% (+/-10%), and freedom from rupture or from type I or type III endoleak was 74% (+/-10%). CONCLUSION: While promising, this midterm experience with commercially available devices highlights the shortcomings of current stent-graft technology. Three significant advancements are required to fulfill the potential of this important treatment method: a stent graft with a durable proximal and distal fixation device, enhanced engineering to accommodate high thoracic aortic fatigue forces, and a mechanism to adapt to aortic arch and visceral segment branches to enable treatment of lesions that extend to or include these vessels.

Aged↗

PubMed2003

Combined open and endovascular repair of a syphilitic aortic aneurysm.

The use of endovascular stent grafts in the repair of thoracic aortic aneurysms has provided an alternative means of treatment, particularly in the high-risk patient who may not tolerate conventional open repair. The combination of conventional surgery and endovascular repair may allow for successful treatment in patients with anatomy unsuitable for repair entirely by endovascular means alone. We present the case of a patient with a syphilitic thoracic aortic aneurysm involving the aortic arch and descending thoracic aorta. He underwent a staged repair with an elephant trunk reconstruction of the aortic arch followed by endovascular repair of the descending thoracic aorta. This is the first reported case of the repair of a syphilitic aneurysm by means of endovascular techniques.

Angioplasty↗

PubMed2003

Importance of extrasegmental vessels for spinal cord blood supply in a chronic porcine model.

OBJECTIVE: Our purpose was to investigate the interaction of the important components of spinal cord blood supply in the pig model to enable its use for future studies of spinal cord protection. METHODS: Twenty-five juvenile pigs (20-22 kg) underwent serial intercostal (IC) or lumbar artery (LA) ligation until disappearance of motor evoked potentials (MEPs). Pigs underwent sequential craniocaudal IC/LA ligation alone (n=5); following clamping of both subclavian arteries (n=4), or clamping of the median sacral artery (MSA, n=4). Animals also underwent serial caudocranial clamping of LA/IC alone (n=4); preceded by clamping of the subclavian arteries (n=4), or of the MSA (n=4). Results were verified by Tarlov's scores and perioperative angiography. RESULTS: All animals with MEP loss suffered postoperative paraplegia. Groups were equivalent with regard to stable arterial pressures (64.6+/-3.1 degrees C) throughout the experiment, temperature (36+/-1.1 degrees C) and other physiological parameters. Mean number of clamped IC/LA before MEP loss for cranio-caudal clamping direction was 12.8+/-0.8 for segmental arteries isolated, 9+/-0.8 if both subclavian arteries were ligated previously and only 4.3+/-0.5 IC if the median sacral artery was clamped before. Mean number of clamped LA for caudo-cranial clamping direction was 5.8+/-0.9 for segmental lumbar arteries, 5.5+/-0.6 LA if both subclavian arteries were ligated previously and 3.5+/-0.6 if the median sacral artery was clamped before. CONCLUSION: This study confirms the importance of lumbar and MSA arteries to cord viability. It documents the interaction of the subclavian and MSA (roughly equivalent to the hypogastric arteries in humans) with segmental vessels in providing spinal cord blood supply. It also provides the physiologic basis for use of the pig model for studies of spinal cord protection in aortic surgery.

Animals↗

PubMed2003

Impact of hypothermic selective cerebral perfusion compared with hypothermic cardiopulmonary bypass on cerebral hemodynamics and metabolism.

OBJECTIVE: Hypothermic selective cerebral perfusion (SCP) is widely used for cerebral protection during aortic arch surgery, but the effect of the absence of systemic perfusion on cerebrovascular dynamics it has never been established. This study explored the physiology of prolonged SCP compared to hypothermic cardiopulmonary bypass (HCPB) in pigs. METHODS: In this blinded protocol, 29 juvenile pigs (20-23 kg) were randomized after cooling on cardiopulmonary bypass (CPB) to 20 degrees C. Group I pigs (n=14) underwent 90 min of SCP, while group II (HCPB, n=15) underwent total body perfusion. Fluorescent microspheres were injected during perfusion and recovery, enabling calculation of total and regional cerebral blood flow (CBF). Cerebrovascular resistance (CVR), oxygen consumption and intracranial pressure (ICP) were also monitored. RESULTS: CBF decreased significantly (P=0.0001) during cooling, but remained at significantly higher levels with SCP than with HCPB throughout perfusion and recovery (P<0.0001). CVR was significantly lower with SCP than with HCPB throughout perfusion (P=0.04). Oxygen consumption fell significantly with cooling (P=0.0001), remained low during perfusion, and rebounded promptly with rewarming; with SCP it was significantly higher than with HCPB throughout the perfusion interval (P=0.03), and remained higher thereafter. ICP rose significantly less with SCP than with HCPB (P=0.02). CONCLUSION: We conclude that, compared with HCPB, SCP results in beneficial cerebral vasodilatation, as evidenced by significantly higher CBF and oxygen consumption during SCP, by prompt recovery of oxygen consumption after rewarming, and by significantly lower ICP during perfusion and in the post-bypass period.

Animals↗

PubMed2003

Recent improvements in outcome with the Novacor left ventricular assist device.

BACKGROUND: The Novacor implantable, electrically powered, wearable, left ventricular assist device (LVAD) has been used as a bridge to transplantation at our institution since 1994. Recent changes in protocol have resulted in a decreased incidence of infections, thromboembolism, and mortality. METHODS: We reviewed the medical records of all 43 patients who received implantable LVADs at the Mount Sinai Medical Center. After 1998, a number of protocol modifications were instituted. Vascular grafts were changed from a low-porosity, woven polyester (Cooley) to a gelatin-sealed, knitted polyester graft (Vascutek), the devices were implanted pre-peritoneally rather than in the posterior rectus sheath, and extensive drainage of the chest and pre-peritoneal pocket was used. The following anti-coagulation regimen was used: low-molecular-weight Dextran for 1 day, initiated after chest tube drainage <50 cc/hour; then IV heparin for 10 to 14 days, beginning at 500 U/hour, slowly increasing partial thromboplastin time to 1.5 to 2 x control; and finally Coumadin, maintaining the international normalized ratio at 2.5 to 3.5. Daily aspirin, 325 mg, was begun on post-operative Day 7. We compared 22 patients who electively underwent surgery before the changes, Group I, with 18 patients treated thereafter, Group II. RESULTS: Groups I and II were well matched with regard to age (47 vs 44 years); cause of heart failure (idiopathic, 50% vs 44%; ischemic, 50% vs 56%), and duration of support (79 vs 76 days). The incidence of thromboembolic cerebrovascular events was significantly less in Group II (6%) than in Group I (23%), p = 0.025. The incidence of bleeding increased mildly in Group I. Pocket infections occurred in 27% of Group I patients vs 11% of Group II patients, p = 0.018. Only 2 patients (11%) in Group II died while receiving device support, vs 7 (32%) in Group I, p = 0.019. CONCLUSIONS: Our results indicate that pre-peritoneal implantation, use of a new generation of vascular grafts, extensive drainage, and a more restricted anti-coagulation regimen improve outcome after Novacor LVAD implantation for advanced heart failure.

Adolescent↗

PubMed2003

Endovascular stent graft repair of abdominal and thoracic aortic aneurysms: a ten-year experience with 817 patients.

OBJECTIVE: On November 23, 1992, the first endovascular stent graft (ESG) repair of an aortic aneurysm was performed in North America. Following the treatment of this patient, we have continued to evaluate ESG over the past 10 years in the treatment of 817 patients. SUMMARY AND BACKGROUND DATA: Abdominal (AAA) or thoracic (TAA) aortic aneurysms are a significant health concern traditionally treated by open surgical repair. ESG therapy may offer protection from aneurysm rupture with a reduction in procedure morbidity and mortality. METHODS: Over a 10-year period, 817 patients were treated with ESGs for AAA (723) or TAA (94). Patients received 1 of 12 different stent graft devices. Technical and clinical success of ESGs was reviewed, and the incidence of procedure-related complications was analyzed. RESULTS: The mean age was 74.3 years (range, 25-95 years); 678 patients (83%) were men; 86% had 2 or more comorbid medical illnesses, 67% of which included coronary artery disease. Technical success, on an intent-to-treat basis was achieved in 93.8% of patients. Primary clinical success, which included freedom from aneurysm-related death, type I or III endoleak, graft infection or thrombosis, rupture, or conversion to open repair was 65 +/- 6% at 8 years. Of great importance, freedom from aneurysm rupture after ESG insertion was 98 +/- 1% at 9 years. There was a 2.3% incidence of perioperative mortality. One hundred seventy five patients died of causes not related to their aneurysm during a mean follow-up of 15.4 months. CONCLUSIONS: Stent graft therapy for aortic aneurysms is a valuable alternative to open aortic repair, especially in older sicker patients with large aneurysms. Continued device improvements coupled with an enhanced understanding of the important role of aortic pathology in determining therapeutic success will eventually permit ESGs to be a more durable treatment of aortic aneurysms.

Adult↗

PubMed2002

Tacrolimus in cardiac transplantation: efficacy and safety of a novel dosing protocol.

BACKGROUND: Although used for more than 20 years, optimal dosing strategies of most immunosuppressants have never been determined. Tacrolimus, one of the newer agents used in solid-organ transplantation, is gaining increasing popularity because of its ability to reverse refractory rejection in cyclosporine-treated patients and its favorable side-effect profile. As with many other immunosuppressive agents, absorption and metabolism vary between individuals, which complicates dosing. METHODS: We hypothesized that a 1-mg dose of tacrolimus may be used to gauge each patient's metabolism. A novel dosing scheme was evaluated to establish the safety and efficacy of this approach. Outcomes were incidence of renal insufficiency and treatment efficacy as assessed by the rejection grade on the first endomyocardial biopsy. RESULTS: The risk of renal insufficiency was low, with only a 3% rise in creatinine at 7 days posttransplant. The risk of renal insufficiency was highest during the first 3 days of tacrolimus therapy, and the change in tacrolimus level during this time was identified as the single best predictor of renal insufficiency. From days 4 to 7, the rise in tacrolimus level had much less influence on renal function. Ninety-two percent of patients had a low- or intermediate-grade first cardiac biopsy. CONCLUSIONS: It was shown that this conservative initial dosing approach, which guarantees renal safety, is not associated with an increased risk of allograft rejection. We conclude that administration of tacrolimus via a tailored protocol soon after transplantation ensures a safe and effective means of immunosuppression.

Adult↗

PubMed2002

Acute type B aortic dissection: surgical therapy.

BACKGROUND: Surgery for acute type B aortic dissection is associated with significant mortality. We report the results for 34 consecutive patients who underwent urgent surgery because they met criteria for operation during the acute phase (< 14 days) of acute type B dissection. METHODS: The average patient age was 64 (32 to 88) years. Indications for surgery were persistent pain (12), threatened exsanguination (18), malperfusion (renal [3], limb [3]), rapid aortic enlargement (4), and uncontrolled hypertension (1). The mean interval from onset of pain to operation was 7 (1 to 14) days. Resection included the proximal descending aorta in 32, the distal aortic arch in 10, extension to the diaphragm in 10, and involved a thoracoabdominal procedure in 3. Surgical techniques included hypothermic circulatory arrest (16 [47%]), distal bypass, monitoring of somatosensory-evoked potentials, sequential intercostal sacrifice (average, 5.6 pairs), cerebrospinal fluid drainage, and steroid administration. RESULTS: There was no hospital mortality. Important complications occurred in 16 patients (47%): 10 respiratory requiring tracheostomy, six infectious, four dialysis, two myocardial infarctions, and two neurologic (one transient stroke, one paraplegia). Mean intensive care unit and hospital stays were 10 (3 to 32) and 35 (7 to 107) days. Survival at 5 and 10 years was 80% and 57%, respectively (mean follow-up, 5.8 years). CONCLUSIONS: Patients meeting criteria for urgent surgery have a low perioperative risk for mortality and paraplegia, and are relatively free from long-term aorta-related complications. These findings warrant consideration of earlier surgery for appropriate patients with acute type B aortic dissection.

Acute Disease↗

PubMed2002

Replacing the ascending aorta and aortic valve for acute prosthetic valve endocarditis: is using prosthetic material contraindicated?

BACKGROUND: The use of prosthetic material (rather than a homograft) for ascending aorta/aortic valve replacement (Bentall procedure) in cases of acute prosthetic valve endocarditis is controversial. We report favorable results using this technique almost exclusively (a homograft was used in only 3 patients with hematological problems) during a 12-year interval. METHODS: Twenty-eight patients (55 +/- 14 years; 22 male) underwent a Bentall procedure for acute prosthetic valve endocarditis between 1988 and 2000. Twenty-five patients had undergone previous aortic valve replacement (1 with concomitant mitral valve replacement, 4 with coronary artery bypass grafting), and 3 had had a previous Bentall operation. The median interval between initial surgery and reoperation was 13 months (range, 1 to 106). Sixty-eight percent of operations were urgent or emergencies. Ninety-three percent of patients had significant aortic regurgitation; complete annuloaortic dehiscence occurred in 71%, and in 57%, an abscess was found. Causative organisms were identified in 25 of 28 patients: Staphylococcus epidermidis (9), Staphylococcus aureus (7), Streptococcus viridans (6), Pseudomonas (2), and Legionella (1). RESULTS: Twenty-three patients had mechanical and 5 had biological valves implanted during the Bentall procedure. Hypothermic circulatory arrest was used in 64%. Hospital mortality was 11%: there was one intraoperative death, and two before discharge (one cardiac, one sepsis). Eighty-nine percent survived without stroke. During follow-up (median, 44.5 months; complete in 92%), 1 patient died of recurrent endocarditis at 4 months. CONCLUSIONS: These results indicate that prosthetic root replacement may be superior to use of a homograft for acute aortic prosthetic valve endocarditis, with only a 4% incidence of recurrent endocarditis and reoperation.

Adult↗

PubMed2002

Bioprosthetic valved conduit aortic root reconstruction: the Mount Sinai experience.

BACKGROUND: Patients requiring aortic root reconstruction who are deemed unable to take anticoagulants offer unique challenges to the surgeon. For these patients, we have been manufacturing composite conduits intraoperatively using stented bioprostheses. METHODS: During the 10-year period from April 1992 until May 2002, 141 patients (105 male, 36 female) from 34 to 88 years of age underwent aortic root reconstruction with biological valved conduits. Diagnoses included dissection (n = 28, 9 acute type A), degenerative (64), atherosclerotic (32), anuloaortic ectasia (9), endocarditis (5), and other causes (3). Preoperative risk factors included hypertension (90), smoking (63), coronary artery disease (48), and diabetes (6). Valved conduits were mainly constructed from pericardial valves and impregnated Dacron grafts. Distal anastomosis was performed open in all cases except 6; the ascending aorta only was replaced in 63 patients, a hemiarch reconstruction was used in 71, and more extensive arch reconstruction in 7. Additional cardiac procedures were performed in 59 patients. RESULTS: Two deaths occurred in the operating room (biventricular failure). Late hospital mortality was 11 of 141 (7.8%) of which 6 (55%) were cardiac, 2 (18.2%) were infectious, 2 (18.2%) were of other complications and 1 (9.1%) was unknown. Three patients (2.1%) sustained permanent and 3 transient strokes. No structural deterioration of the valve and an approximately 86% freedom from thromboembolic events was observed during 5 years. CONCLUSIONS: For patients for whom anticoagulation is contraindicated or undesirable, reconstruction of the aortic root with a stented bioprosthetic valved conduit offers an acceptable alternative to mechanical prostheses.

Adult↗

PubMed2002

Aortic arch replacement using a trifurcated graft and selective cerebral antegrade perfusion.

BACKGROUND: Aortic arch aneurysm repair remains associated with considerable mortality and risk of cerebral complications. We present results of a technique utilizing a three-branched graft for arch replacement, deep hypothermic circulatory arrest (HCA), and selective antegrade cerebral perfusion (SCP). METHODS: Between March 2000 and November 2001, 22 patients (11 female) aged 40 to 77 years (mean 64 +/- 11.2) underwent arch replacement utilizing the trifurcated-graft technique. Serial anastomosis of the branched graft to individual cerebral vessels was carried out during HCA, followed by arch reconstruction during SCP through the graft. All 22 patients had surgery electively. Eight patients (36%) had undergone previous aortic surgery. In 19 patients, arch replacement was part of an elephant trunk procedure; 2 patients had Bentall operations and 1 had isolated arch replacement. Concomitant coronary artery bypass grafting was performed in 6 patients (27%). Mean HCA duration was 30 +/- 6 minutes at a mean temperature of 11.4 +/- 0.8 degrees C. Mean duration of SCP was 52 +/- 18 minutes. RESULTS: Adverse outcome--death before hospital discharge or permanent stroke or both--occurred in 2 patients (9%). Two patients experienced transient neurologic dysfunction (9%). Two patients (9%) developed renal failure requiring short-term hemodialysis and pulmonary complications occurred in 2 patients. CONCLUSIONS: Cerebral protection and prevention of atheroembolism remain challenges in aortic arch reconstruction. To reduce neurologic complications we developed an aortic arch reconstruction technique in which a trifurcated graft is anastomosed to the brachiocephalic vessels during HCA, reducing the risk of embolization while minimizing cerebral ischemia by permitting antegrade cerebral perfusion as arch repair is completed.

Adult↗

PubMed2002

Impact of high intracranial pressure on neurophysiological recovery and behavior in a chronic porcine model of hypothermic circulatory arrest.

OBJECTIVE: This review was undertaken to determine whether high intracranial pressure (ICP) during reperfusion after hypothermic circulatory arrest (HCA) correlates with evidence of suboptimal cerebral protection in a chronic porcine model. METHODS: In concurrent studies of cerebral protection, 48 control pigs (24-31 kg) underwent 90 min of HCA at 20 degrees C using a strictly standardized protocol. Hemodynamic measurements, ICP and neurophysiological data (EEG, SSEP) were assessed before HCA and until 3 h postoperatively. ICP was measured using a Codman microtip catheter inserted directly into brain parenchyma. Neurological/behavioral evaluation (9=full recovery) was carried out daily through postoperative day (POD) 3. RESULTS: There were no significant hemodynamic or metabolic differences between individual animals. ICP (mmHg) increased significantly for the first 3 h after HCA: from baseline levels of 6.2+/-2.1 to 10+/-2.6 at 1 h, 11+/-3.2 at 2 h and 10+/-3.6 mmHg at 3 h; P<0.001 for the trend. EEG recovery 3 h after HCA was observed in 13 animals (27%), and correlated with lower ICP during reperfusion (P<0.001): with each 1 mmHg increase in ICP at 3 h, the odds of early EEG recovery decreased by a factor of 0.72. Lower ICP during reperfusion was also significantly associated with higher behavioral scores on POD 1 and 2, P<0.001. CONCLUSIONS: A significant rise in ICP may help explain the prolonged obtundation and confusion often seen clinically after HCA. If these small but consistent increases in ICP contribute to rather than reflect ischemic neuronal damage, simple maneuvers to reduce ICP may improve cerebral recovery after HCA.

Animals↗

PubMedDate not supplied

Aortic arch and descending thoracic aortic aneurysms: experience with stent grafting for second-stage "elephant trunk" repair.

Reconstruction of aortic arch and descending thoracic aortic aneurysms (TAAs) is technically challenging and associated with significant morbidity and mortality. We report our experience with extensive TAAs using a two-stage "elephant trunk" repair, with the second stage completed using an endovascular stent graft (ESG). Over 6 years, 111 patients underwent ESG treatment of TAAs at Mount Sinai Medical Center. Twelve of these patients were referred for ESG placement for the second stage of elephant trunk reconstruction because comorbidities placed them at high risk of open surgical repair. Our database was analyzed for technical and clinical success and perioperative complications. The mean follow-up was 11.8 months (range 1-64 months). Twelve patients (five women and seven men) with a mean age of 69 +/- 10 years underwent repair of their distal aortic arch and descending TAAs. These aneurysms included nine atherosclerotic aneurysms, one pseudoaneurysm, and two penetrating atherosclerotic ulcers. Three patients were symptomatic. Stent graft repair was technically successful in 91.7% or 11 of 12 patients. Excessive aortic arch tortuosity resulted in failure to deploy a stent graft in one patient. An antegrade approach through the open elephant trunk was used in two patients with severe iliac occlusive disease. Endoleaks (type 2) were identified in two patients with no aneurysm expansion; however, a 14 mm expansion over 1 year occurred in a patient with no identifiable endoleak. One early mortality occurred in a patient with a ruptured 6 cm infrarenal AAA after successful exclusion of the 8 cm TAA. Second-stage elephant trunk reconstruction of an extensive TAA using an ESG is effective in the short term. Its long-term durability remains to be determined.

Aneurysm, False↗

PubMedDate not supplied

Importance of extrasegmental vessels for spinal cord blood supply in a chronic porcine model.

UNLABELLED: IObjective: Our purpose was to investigate the interaction of the important components of spinal cord blood supply in the pig model to enable its use for future studies of spinal cord protection. METHODS: 25 juvenile pigs (20-22 Kg) underwent serial intercostal (IC) or lumbar artery (LA) ligation until disappearance of motor evoked potentials (MEPs). Pigs underwent sequential craniocaudal (IC/LA ligation alone (n=5); following clamping of both subclavian arteries (n=4)m, or clamping of the median sacral artery (MSA, n=4); preceded by clamping of the subclavian arteries (n=4), or of the MSA (n=4). RESULTS were verified by Tarlov's scores and perioperative angiography. RESULTS: All animals with MEP loss suffered postoperative paraplegia. Groups were equivalent with regard to stable arterial pressures throughout the experiment, temperature and other physiological parameters. Mean number of clamped IC/LA before MEP loss for cranio-caudal clamping direction was 12.8 +/-0.8 for segmental arteries isolated, 9 +/-0.8 if both subclavian arteries were ligated previously and only 4.3 +/- 0.5 IC if the median sacral artery was clamped before. Mean number of clamped LA for caudo-cranial clamping direction was 5.8 +/-0.9 for segmental lumbar arteries, 5.5 +/-0.6 LA if both subclavian arteries were ligated previously and 3.5 +/-0.6 if the median sacral artery was clamped before. CONCLUSION: This study confirms the importance of lumbar and MSA arteries to cord viability. It documents the interaction of the subclavian and MSA (roughly equivalent to the hypogastric arteries in humans) with segmental vessels in providing spinal cord blood supply. It also provides the physiologic basis for use of the pig model for studies of spinal cord protection in aortic surgery.

Animals↗