Biomedical subjects

Randall B Griepp

Publications and source records attributed to Randall B Griepp.

At least 19 recordsLinked to original sources

PubMed2006

The fate of the distal aorta after repair of acute type A aortic dissection.

OBJECTIVES: The residual aorta's behavior after repair of acute type A dissection is incompletely understood. We analyzed segmental growth rates, distal reoperation, and factors influencing long-term survival. METHODS: One hundred seventy-nine consecutive patients (70% male; mean age, 60 years) with acute type A dissection underwent aggressive resection of the intimal tear and open distal anastomosis (1986-2003). Hospital mortality was 13.4%. Survivors had serial computed tomographic scans: digitization yielded distal segmental dimensions. Segment-specific average rates of enlargement and factors influencing faster growth were analyzed. Distal reoperations and patient survival were examined. RESULTS: Eighty-nine (57%) patients had imaging data sufficient for growth rate calculations. The median diameters after repair were as follows: aortic arch, 3.6 cm; descending aorta, 3.7 cm; and abdominal aorta, 3.2 cm. Subsequent growth rates were 0.8, 1.0, and 0.8 mm/y, respectively. Initial size of greater than 4 cm (P = .005) and initial diameter of less than 4 cm with a patent false lumen (P = .004) predicted greater growth in the descending aorta, and male sex (P = .05) significantly affected growth in the abdominal aorta. No significant factors were found for the aortic arch. There were 25 distal aortic reoperations (16 patients), and risk of reoperation was 16% at 10 years. Risk factors reducing long-term survival after repair of acute type A dissection included age (P < .0001), new neurological deficit at presentation (P = .04), absence of preoperative thrombus in the false lumen of the ascending aorta (P = .03), and a patent distal false lumen postoperatively (P = .06) but not distal reoperation. CONCLUSIONS: Growth of the distal aorta after repair of acute type A dissection is typically slow and linear. Distal reoperation is uncommon, and late risk of death is approximately twice that of a healthy population.

Acute Disease↗

PubMed2006

Thoracic and thoracoabdominal aneurysm repair: is reimplantation of spinal cord arteries a waste of time?

BACKGROUND: The impact of different strategies for management of intercostal and lumbar arteries during repair of thoracic and thoracoabdominal aortic aneurysms (TAA/A) on the prevention of paraplegia remains poorly understood. METHODS: One hundred consecutive patients with intraoperative monitoring of motor evoked potentials (MEP) and somatosensory evoked potentials (SSEP) during TAA/A repair involving serial segmental artery sacrifice (October 2002 to December 2004) were reviewed. RESULTS: Operative mortality was 6%. The median intensive care unit stay was 2.5 days (IQ range: 1-4 days), and the median hospital stay 10.0 days (IQ range: 8-17 days). Potentials remained unchanged during the course of serial segmental artery sacrifice, or could be returned to baseline levels by anesthetic and blood pressure manipulation, in 99 of 100 cases. An average of 8.0 +/- 2.6 segmental artery pairs were sacrificed overall, with an average of 4.5 +/- 2.1 segmental pairs sacrificed between T7 and L1, where the artery of Adamkiewicz is presumed to arise. Postoperative paraplegia occurred in 2 patients. In 1, immediate paraplegia was precipitated by an intraoperative dissection, resulting in 6 hours of lower body ischemia. A second ambulatory patient had severe paraparesis albeit normal cerebral function after resuscitation from a respiratory arrest. CONCLUSIONS: With monitoring of MEP and SSEP, sacrifice--without reimplantation--of as many as 15 intercostal and lumbar arteries during TAA/A repair is safe, resulting in acceptably low rates of immediate and delayed paraplegia. This experience suggests that routine surgical implantation of segmental vessels is not indicated, and that, with evolving understanding of spinal cord perfusion, endovascular repair of the entire thoracic aorta should ultimately be possible without spinal cord injury.

Adult↗

PubMed2005

Use of a maze to detect cognitive dysfunction in a porcine model of hypothermic circulatory arrest.

BACKGROUND: Hypothermic circulatory arrest (HCA) can result in cognitive impairment not reflected by histopathology or gross neurologic observation. We tested the sensitivity of two multi-room maze tasks in detecting cerebral dysfunction after HCA in pigs. METHODS: Twenty-seven pigs were studied, divided between two tasks. 13 underwent 90 minutes HCA at 20 degrees C and were trained from postoperative day (POD) 7; 14 were unoperated controls. The maze includes a holding area, 8 rooms, and a center hallway. One piece of apple is placed in each baited room on each of 10 days of learning evaluation. After a pig enters a room, doors to all other rooms close, and the pig must return to the holding area. In task 1, 6 of 8 rooms were baited, and each day's session ended when each baited room had been entered, or after 20 trials. In task 2, initially only the right- or left-sided rooms were baited. Pigs were evaluated each day until they entered 4 baited rooms, or for 15 trials; the process was then repeated, baiting the other side. RESULTS: Intraoperative physiology and postoperative recovery showed no differences between task 1 or 2 pigs. Task 1 did not distinguish between control and HCA groups (p = 0.5), but task 2 revealed significantly (p = 0.04) better learning in controls. CONCLUSIONS: The significantly poorer performance of pigs after HCA suggests that the reversal of baited rooms in task 2 provides the sensitivity to detect cognitive dysfunction. The maze is a promising tool to investigate in pigs the mild cerebral damage often seen after HCA.

Animals↗

PubMed2005

Long-term integrity of teflon felt-supported suture lines in aortic surgery.

BACKGROUND: Although the ultimate success of aortic operations depends upon the integrity of graft-to-aorta anastomoses, little is known about different techniques used to assure their longevity. We report the incidence of reoperation for suture line disruptions arising from anastomoses using reinforcement with Teflon felt. METHODS: Since 1987, 1475 patients underwent 2281 anastomoses in the thoracic aorta (mean 1.55/anastomoses per patient). All patients were followed with at least yearly computed tomographic scans, for a total follow-up of 6483.8 patient-years. Those requiring reoperation were reviewed retrospectively for evidence of suture line disruption. RESULTS: Only 34 patients, with a mean age of 55.1 years old (range 26-85 years old) underwent reoperation for suture-line disruptions following vascular graft-to-aorta anastomosis using Teflon felt. The previous operation was a Bentall procedure in 15 (44%); ascending aorta replacement in 9 (26%); total arch replacement in 6 (18%); descending aorta replacement in 2 (6%); thoracoabdominal repair in 1 (3%); and sinus of Valsalva repair in 1 (3%). The incidence of suture line disruption was 0.0052 per patient-year, and 0.0034 per anastomosis-year. The mean interval between operations was 55.9 months (range 4-180 months). In 21%, the pseudoaneurysm originated from the proximal anastomosis; in 71% from the distal anastomosis; in 3% from both; in 3% from the innominate artery; and in 3% from a sinus of Valsalva repair. In only 1 patient was there evidence of infection. Reoperation involved ascending aorta replacement in 11 patients, and total arch replacement in 13 patients. Adverse outcome, such as hospital death or permanent stroke, occurred in 8% (3 patients). CONCLUSIONS: Use of Teflon felt to support aortic suture lines yields a very low incidence of suture line disruptions: 1 per 191 patient-years, or 1 per 296 anastomosis-years. Teflon felt reinforcement provides a secure, long-lasting graft-to-aorta anastomosis with minimal risk of infection.

Adolescent↗

PubMed2005

Aortic arch replacement using a trifurcated graft: simple, versatile, and safe.

BACKGROUND: Hypothermic selective antegrade cerebral perfusion during aortic arch replacement may prevent adverse neurologic sequelae. It can be provided via balloon-tipped catheters or a branched graft sewn to the brachiocephalic vessels. We report a consecutive series of total arch replacement using a trifurcated graft. METHODS: From September 1999 through October 2004, 109 patients underwent nonemergent total arch replacement using this technique. The graft, placed during a period of hypothermic circulatory arrest, was used for selective cerebral perfusion during the arch reconstruction. RESULTS: Adverse outcomes were seen in 9 (8.3%) patients: hospital death in 5 (4.6%), and stroke in 5 (4.6%). Transient neurologic dysfunction was noted in 6 (5.5%) patients. Mean duration of hypothermic circulatory arrest was 31.2 +/- 6.6 minutes and selective cerebral perfusion was 65.3 +/- 20.9 minutes. Reoperation for bleeding was required in 3 (2.8%) patients and prolonged intubation in 15 (13.8%). Median intensive care unit stay was 3 days (interquartile range 2-4; range, 1 to 108) and hospital stay was 9 (interquartile range 8-15; range, 5 to 108). CONCLUSIONS: The trifurcated graft technique results in low rates of perioperative mortality, temporary neurologic dysfunction, and stroke. It may reduce cerebral embolization as it requires no instrumentation of the aortic arch to establish selective cerebral perfusion and, although it mandates hypothermic circulatory arrest to place the graft, this interval is reliably brief enough to fall within accepted safe limits. This strategy leaves no residual arch tissue behind, and allows placement of an elephant trunk proximal to one or more arch vessels if anatomically indicated.

Adult↗

PubMed2005

Cooling to 10 degrees C and treatment with Cyclosporine A improve cerebral recovery following prolonged hypothermic circulatory arrest in a chronic porcine model.

OBJECTIVE: This study was undertaken to assess whether cooling to 10 degrees C and/or treatment with Cyclosporine A (CsA) can reduce neurological injury during prolonged hypothermic circulatory arrest (HCA) in a chronic animal model. METHODS: In this blinded study, 24 pigs (20-23 kg) were randomized to HCA for 90 min at 20 degrees C (n=8), at 10 degrees C (n=8), or at 10 degrees C with 5 mg/kg CsA (n=8). CsA (or placebo) were given intravenously before and for 3 days after HCA. Hemodynamics and neurophysiological data were monitored periodically throughout the experiment and for 3 h after HCA, as well as intracranial pressure (ICP), which has been shown to correlate with outcome. Daily neurological/behavioral evaluation (mental status, coordination and appetite; 12=normal and 0=coma or death) was carried out until sacrifice on postoperative day (POD) 3. RESULTS: Overall survival rate was 83.3%: one 20 degrees C control, two 10 degrees C controls, and one 10 degrees C/CsA pig died and were replaced. Basic hemodynamic data revealed no significant differences between groups. ICP differed significantly among the groups during the first 3 h postoperatively (P=0.003 by repeated measures ANOVA); it was higher in the 20 degrees C group than in the 10 degrees C/CsA or 10 degrees C control groups. Recovery of visual evoked potentials was significantly better in the 10 degrees C/CsA group than in the 10 degrees C control group; no recovery was seen by 3 h in the 20 degrees C control group. Postoperative behavioral scores also differed significantly between the groups, P=0.03: a good behavioral outcome--a score >9 on POD3--was more prevalent among CsA-treated pigs (75%) than among 10 degrees C controls (50%), or 20 degrees C controls (12.5%, P=0.06). CONCLUSIONS: The data suggest that cooling to 10 degrees C and CsA treatment are both of benefit in improving cerebral recovery after HCA when compared with untreated 20 degrees C controls, and may be synergistic.

Animals↗

PubMed2005

Composite aortic root replacement in acute type A dissection: time to rethink the indications?

OBJECTIVE: The indications for aortic root replacement in acute type A dissection are unclear. We reviewed the immediate and long-term outcome of consecutive patients in a series in which a low-threshold policy of composite aortic root replacement had evolved. METHODS: From a prospectively compiled aortic surgery database, we identified 162 patients who had either supracoronary interposition grafting, Group A (n=89), or composite root replacement, Group B (n=73) for acute type A dissection. Patients receiving total arch replacements were excluded. Operative and clinical details were analyzed and patient survival was compared to an age and gender matched census cohort. Need for reoperation on the proximal or distal aorta was also noted. Follow-up totaled 795.5 patient-years. RESULTS: Hospital mortality rates were identical in both groups (12.3%: 11 deaths in group A; 9 in group B). Chronic pulmonary disease, diabetes, malperfusion, hemodynamic compromise and aortic root dilatation were independent risk factors for hospital death. Actuarial survival estimates at 1, 5 and 10 years were 79% (71-88%), 64% (53-75%), and 55% (41-68%) for group A, and 79% (70-86%), 73% (62-83%), and 65% (52-78%) for group B (P=0.48). Age and operative patency of the ascending false lumen were independent risk factors for death after hospital discharge. Proximal aortic reoperation was required for four patients in group A and none in group B (P=0.085). CONCLUSION: A strategy of replacement rather than repair of the dissected aortic root for specific indications in type A dissection yielded high survival and low proximal reoperation rates. These results support an aggressive policy of composite root replacement in acute type A dissection.

Acute Disease↗

PubMed2005

Optimal pH strategy for selective cerebral perfusion.

OBJECTIVE: Selective cerebral perfusion (SCP) affords brain protection superior to hypothermic circulatory arrest (HCA) for prolonged aortic arch procedures. Optimal pH strategy for HCA is controversial; for SCP it is unknown. We compared pH strategies during SCP in a survival pig model. METHODS: Twenty juvenile pigs (26+/-2.4 kg), randomized to alpha-stat (n=10) or pH-stat (n=10) management, underwent cooling to 20 degrees C on cardiopulmonary bypass (CPB) followed by 90 min of SCP at 20 degrees C. SCP was conducted with a mean pressure of 50 mmHg and hematocrit of 22.5%. Using fluorescent microspheres and sagittal sinus blood sampling, cerebral blood flow (CBF) and oxygen metabolism (CMRO2) were assessed at the following time points: baseline, after 30 min cooling (20 degrees C), 30 min of SCP, 90 min of SCP, 15 min post-CPB and 2h post-CPB. Visual evoked potentials (VEP) were assessed at baseline and monitored for 2h during recovery. Neurobehavioral recovery (10=normal) was assessed in a blinded fashion for 7 postoperative days. RESULTS: There were no significant differences between the groups at baseline. CBF was significantly higher at the end of cooling, and after 30 and 90 min of SCP in the pH-stat group (P=0.02, 0.007, 0.03). CMRO2 was also higher with pH-stat (P=0.06, 0.04, 0.10). Both groups showed prompt return to values close to baseline after rewarming (P=ns). VEP suggested a trend towards improved recovery in the alpha-stat group at 2h post-CPB, P=0.15. However, there were no significant differences in neurobehavioral score: (alpha-stat versus pH-stat) median values 7 and 7.5 on day 1; 9 and 9 on day 4, and 10 and 10 on day 7. CONCLUSIONS: These data suggest that alpha-stat management for SCP provides more effective metabolic suppression than pH-stat, with lower CBF. Clinically, the better preservation of cerebral autoregulation during alpha-stat perfusion should reduce the risk of embolization.

Animals↗

PubMed2005

Optimal temperature for selective cerebral perfusion.

OBJECTIVE: Although combinations of hypothermic circulatory arrest and antegrade selective cerebral perfusion are used for cerebral protection during arch surgery, there is no consensus regarding the optimal temperature during selective cerebral perfusion. This study explored the effect of different temperatures during selective cerebral perfusion on cerebral metabolism and neurologic outcome. METHODS: In this blinded study, 40 pigs (19-21 kg) were randomized into 4 groups after 30 minutes of hypothermic circulatory arrest at 20 degrees C. During a 60-minute interval of selective cerebral perfusion, with flow regulated to maintain a perfusion pressure of 50 mm Hg, pigs were perfused at 10 degrees C, 15 degrees C, 20 degrees C, and 25 degrees C. Fluorescent microspheres enabled calculation of cerebral blood flow during perfusion and recovery. Hemodynamics, intracranial pressure, cerebrovascular resistance, and oxygen consumption were also monitored. Behavioral scores were obtained for 7 days after surgery. RESULTS: Cerebral blood flow decreased significantly ( P < .002) during cooling in all groups: it was significantly higher throughout selective cerebral perfusion in the 20 degrees C to 25 degrees C versus the 10 degrees C to 15 degrees C group ( P = .0001) and remained higher during recovery ( P = .0001). Oxygen consumption decreased significantly with cooling ( P = .0001), remained low during perfusion, and rebounded with rewarming but was significantly lower at 10 degrees C to 15 degrees C than at 20 degrees C to 25 degrees C throughout selective cerebral perfusion ( P = .003) and after CPB was discontinued ( P = .001). Postoperative behavioral scores were significantly better after selective cerebral perfusion at 10 degrees C to 15 degrees C than at 20 degrees C to 25 degrees C ( P = .001). CONCLUSIONS: This study suggests that selective cerebral perfusion at 10 degrees C to 15 degrees C provides better cerebral protection than selective cerebral perfusion at 20 degrees C to 25 degrees C, even though oxygen consumption remains low for hours after selective cerebral perfusion at 10 degrees C to 15 degrees C. Prompt return of metabolism to baseline levels after hypothermic circulatory arrest/selective cerebral perfusion does not necessarily predict superior behavioral outcome.

Animals↗

PubMed2004

Axillary artery cannulation: routine use in ascending aorta and aortic arch replacement.

BACKGROUND: Ideal perfusion during ascending aorta-arch surgery should allow easy implementation of antegrade cerebral perfusion while avoiding atheroembolization or false lumen perfusion in dissections. We report favorable experience with direct axillary artery cannulation. METHODS: Between 1999 and 2003, 284 patients with a mean age of 62.2 years (25 to 85), underwent axillary artery cannulation using a right angle wire-reinforced catheter. During this interval, attempted axillary cannulation was abandoned in only 14 patients because of inadequate backflow or other complications. Eighty-five patients were female. Severe aortic arteriosclerosis or degeneration was present in 209, aortic dissection in 63, and Marfan disease or aortitis in 12. The Bentall procedure was done in 144 patients, arch replacement in 86, the Yacoub procedure in 18, thoracoabdominal aneurysm repair in 16, and coronary artery bypass grafting in 20. Reoperations were at 30.2%. RESULTS: Adverse outcome (hospital death or permanent stroke) occurred in 6.6% (n = 19). Thirteen patients (4.6%) died before hospital discharge, and 13 patients (4.6%; 9 of whom died) suffered permanent stroke. Transient neurologic dysfunction occurred in 9.2% (n = 26). Mean duration of hypothermic circulatory arrest, used in 246 patients, was 26 +/-7 minutes. Mean duration of antegrade cerebral perfusion, used in 139 patients, was 47 +/- 23 minutes. In 93%, the right axillary artery was cannulated. Complications included 2 cases (0.7%) of brachial plexus injury (one transient), and 3 (1%) of localized dissection. CONCLUSIONS: Our results suggest that axillary artery cannulation, successful in 95% of patients, may be the optimal technique for reducing perfusion-related morbidity and adverse outcome in operations for acute dissection, atherosclerotic, and degenerative aneurysmal disease. It deserves serious consideration in all patients older than 65 requiring cardiopulmonary bypass.

Adult↗

PubMed2004

Mild hypothermia protects the spinal cord from ischemic injury in a chronic porcine model.

OBJECTIVES: During thoracoabdominal aortic aneurysm repair, prolonged compromise of spinal cord blood supply can result in irreversible spinal cord injury. This study investigated the impact of mild hypothermia during aortic cross-clamping on postoperative paraplegia in a chronic porcine model. METHODS: The thoracic aorta was exposed and cross-clamped in 30 juvenile pigs (20-22 kg) for different intervals at normothermia (36.5 degrees C), and during mild hypothermia (32.0 degrees C). Three pigs were evaluated at each time and temperature. Myogenic motor-evoked potentials (MEPs) were monitored, and postoperative recovery evaluated using a modified Tarlov score. RESULTS: There were no significant hemodynamic or metabolic differences between individual animals, and the groups had equivalent arterial pressures (mean 64.3+/-3.6 mmHg). Time to recovery of MEPs correlated with severity of injury; all animals with irreversible MEP loss suffered postoperative paraplegia. At normothermia, animals with 20 min of aortic cross-clamping emerged with normal motor function, but those cross-clamped for 30 min suffered paraplegia. With mild hypothermia, animals tolerated 50 min of aortic cross-clamping without evidence of neurologic injury, but were all paraplegic after 70 min of ischemia. Animals appeared to recover normal motor function after 60 min of aortic cross-clamping at hypothermia initially, but exhibited delayed-onset paraplegia 36 h postoperatively. CONCLUSIONS: Our observations indicate that mild hypothermia dramatically increases the tolerance of the spinal cord to ischemia in the pig, and therefore suggests that cooling to 32.0 degrees C should be encouraged during surgery which may compromise spinal cord blood supply. An ischemic insult of borderline severity may result in delayed paraplegia.

Animals↗

PubMed2004

Technical advances in total aortic arch replacement.

BACKGROUND: We compared the effects of using hypothermic circulatory arrest (HCA) alone, HCA combined with selective cerebral perfusion (SCP), and use of SCP with a trifurcated graft (T) on outcome after aortic arch repair. METHODS: One hundred fifty patients, median age 66 years (range, 27 to 85), underwent total arch replacement between 1988 and 2002; 75 were female. We retrospectively compared the results of three patient groups roughly comparable with regard to preoperative risk factors: 45 patients using HCA beginning in 1988; 67 patients using HCA/SCP beginning in 1994; and 38 patients utilizing a trifurcated arch graft in conjunction with SCP through the axillary artery (HCA/SCP/T) since 2000. The groups were well matched with regard to median age (66, 68, and 66 years), urgency (emergent 11%, 13%, 5%; urgent 24%, 9%, 18%; and elective 64%, 78%, 76%), and several other known risk factors (p = not significant). RESULTS: An adverse outcome-hospital death or permanent stroke-occurred in 14%: in 16% with HCA, in 16% with HCA/SCP, and in 8% with HCA/SCP/T. Transient neurologic dysfunction among patients surviving without stroke was lower with HCA/SCP/T (11%) than with HCA (33%) or HCA/SCP (17%). Mean duration of HCA was 52 +/- 16 minutes with HCA alone versus 45 +/- 10 minutes with HCA/SCP and 31 +/- 7 minutes with HCA/SCP/T (p < 0.0001 for groups HCA and HCA/SCP combined versus HCA/SCP/T). Mean duration of SCP was 57 +/- 25 minutes with HCA/SCP versus 62 +/- 24 minutes with HCA/SCP/T (p = not significant). Comparison of the groups of patients who had comparable preoperative risk factors for adverse outcome showed a trend toward lower adverse outcome and transient neurologic dysfunction rates using HCA/SCP/T; a significant reduction in respiratory (p < 0.001), infectious (p = 0.015) and cardiac (p = 0.005) complications in HCA/SCP/T compared with the earlier groups; and significantly shorter durations of intensive care (p < 0.0001) and hospitalization (p = 0.004). CONCLUSIONS: Our results suggest that HCA/SCP is superior to HCA alone for preventing cerebral injury during operations on the aortic arch. By further reducing embolic risk as well as duration of HCA, HCA/SCP/T with axillary artery cannulation may be the optimal technique for averting adverse outcomes, reducing complications, and shortening hospital stay after aortic arch repair.

Adult↗

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

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↗