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Biomedical subjects

T M Sundt

Publications and source records attributed to T M Sundt.

At least 19 recordsLinked to original sources
PubMed2005

Is early anticoagulation with warfarin necessary after bioprosthetic aortic valve replacement?

OBJECTIVES: Freedom from anticoagulation is the principal advantage of bioprosthesis; however, the American Heart Association/American College of Cardiology and the American College of Chest Physicians guidelines recommend early anticoagulation with heparin, followed by warfarin for 3 months after bioprosthetic aortic valve replacement. We examined neurologic events within 90 days of bioprosthetic aortic valve replacement at our institution. METHODS: Between 1993 and 2000, 1151 patients underwent bioprosthetic aortic valve replacement with (641) or without (510) associated coronary artery bypass. By surgeon preference, 624 had early postoperative anticoagulation (AC+) and 527 did not (AC-). In the AC- group, 410 patients (78%) received antiplatelet therapy. Groups were similar with respect to gender (female, 36% AC+ vs 40% AC-, P = .21), hypertension (64% AC+ vs 61%, P = .27), and prior stroke (7.6% AC+ vs 8.5% AC-, P = .54). The AC+ group was slightly younger than the AC- group (median, 76 years vs 78 years, P = .006). RESULTS: Operative mortality was 4.1% with 43 (3.7%) cerebrovascular events within 90 days. Excluding 18 deficits apparent upon emergence from anesthesia, we found that postoperative cerebrovascular accident occurred in 2.4% of AC+ and 1.9% AC- patients. By multivariable analysis, the only predictor of operative mortality was hypertension ( P < .0001). Postoperative cerebrovascular accident was unrelated to warfarin use ( P = .32). The incidence of mediastinal bleeding requiring reexploration was similar (5.0% vs 7.4%), as were other bleeding complications in the first 90 days (1.1% vs 0.8%). No variables were predictive of bleeding by multivariate analysis. CONCLUSIONS: Although these data do not address the role of antiplatelet agents, early anticoagulation with warfarin after bioprosthetic aortic valve replacement did not appear to protect against neurologic events.

Aged↗
PubMed2004

Flaccid quadriplegia due to necrotizing myopathy following lung transplantation.

Critical illness myopathy (CIM) which is common after sepsis and multiorgan failure also has been described after organ transplantation. Prior reports of CIM after lung transplantation have not recorded a necrotizing myopathy. We present a 42-year-old man who developed a necrotizing critical illness myopathy following bilateral orthotopic lung transplantation. In addition we provide pathological confirmation that the ventral roots, spinal cord and the rest of the neuraxis are preserved in this condition. Extensive muscle necrosis is documented.

Adult↗
PubMed2003

Mitral valve repair in the elderly: operative risk for patients over 70 years of age is acceptable.

AIM: Mitral valve repair for degenerative disease is widely accepted. Because of low risk and excellent late outcomes, surgical intervention is recommended increasingly early when repair appears possible. The place of repair vis a vis continued medical therapy in the elderly, however, is less well defined as there are scant data on their surgical risk. We reviewed our recent results with mitral valvuloplasty for degenerative disease with attention to the influence of age. METHODS: Thirty-day results of mitral valvuloplasty for degenerative disease between January 1996 and April 2000 were examined retrospectively. Patients with ischemic etiology were excluded. Results among those over age 70 years were compared with younger patients. RESULTS: Of 140 patients (78 men and 62 women) aged 27 to 91 (mean 62+/-13) years (44 gs;70 years of age), 61 underwent isolated mitral valvuloplasty, 71 mitral valvuloplasty and coronary artery bypass, and 8 mitral valvuloplasty with other procedures. By multivariate analysis preoperative cardiogenic shock (0.001), but not age, was as a risk factor for death. Among patients stratified by age gs; or <70, there were differences in atrial fibrillation (47.7% vs 29.2%, p=0.03), prolonged ventilation (31.8% vs 15.6%, p=0.03) and hospital stay (median 9.5, range 5-285 vs median 6.5, range 2-36, p=0.001), but not 30-day readmission (15.9% vs 22.9%) or death (5.2% vs 9.1%, p=0.49). CONCLUSION: Operative results for mitral valvuloplasty in the elderly are acceptable. Surgery should not be withheld on the basis of age alone.

Adult↗
PubMed2001

Does the extent of proximal or distal resection influence outcome for type A dissections?

BACKGROUND: The extent of proximal and distal aortic resection that should be performed for acute type A aortic dissections remains controversial. METHODS: From 1984 to 1999, 119 patients underwent repair of an acute type A dissection. Distal resection was to the ascending aorta in 78 (66%) and hemiarch in 41 (34%) patients. Proximally, the aortic valve was preserved in 69 (58%) patients, 40 (34%) underwent composite valve grafting, and 10 (8%) underwent separate graft and valve replacement. RESULTS: Operative mortality was higher for separate graft and valve (50%+/-16%) than for valve preservation (16%+/-5%) or composite grafts (20%+/-7%) (p < 0.05). Hemiarch replacement did not increase operative risk compared to distal reconstruction to the ascending aorta (17%+/-6% versus 22%+/-5%, p > 0.71). At 10 years, freedom from reoperation was 81%+/-7% and long-term survival was 60%+/-8%, but neither was related to the proximal or distal surgical technique (p > 0.15). Risk factors for late reoperation included a nonresected primary tear and Marfan syndrome (p < 0.05). CONCLUSIONS: An aggressive surgical approach, including a full root or hemiarch replacement, is not associated with increased operative risk and should be considered when type A dissections extensively involve the valve, sinuses, or arch.

Acute Disease↗
PubMed2001

Oxygenator support for partial left-heart bypass.

Partial left-heart bypass provides circulatory support and distal perfusion for repair of thoracic and thoracoabdominal aortic disease without requiring full anticoagulation. Unfortunately some patients, such as those with significant lung contusion in the setting of trauma or those with severe chronic obstructive pulmonary disease and degenerative aneurysms, do not tolerate single-lung ventilation. We have recently modified our left-heart bypass circuit in selected cases to provide supplementary oxygenation, making this technique more broadly applicable.

Aortic Aneurysm↗
PubMed2001

Influence of internal mammary artery grafting and completeness of revascularization on long-term outcome in octogenarians.

BACKGROUND: It has been well established that complete revascularization with internal mammary artery (IMA) grafting is important in young patients undergoing coronary artery bypass grafting (CABG). Applying these principles to octogenarians remains controversial. METHODS: From 1986 to 1999, 358 consecutive patients aged 80 to 94 years underwent CABG. Revascularization was complete in 291 (81%) and incomplete in 67 (19%). The IMA was used in 231 (65%) cases. RESULTS: Operative mortality was 7% +/- 1%, but was not statistically different with or without IMA grafting (IMA 5% +/- 2% versus no IMA 10% +/- 3%, p = 0.11) or complete revascularization (p > 0.41). Midterm survival improved with IMA grafting (70% +/- 3% versus 56% +/- 5% at 4 years, p < 0.03; 36% +/- 4% versus 29% +/- 5% at 8 years, p < 0.08), but was not significant beyond 8 years. Among 138 survivors, those with IMA grafts were more likely to be angina free (82% versus 53%, p < 0.001) and in New York Heart Association class I (60% versus 36%, p < 0.03). Survival, recurrent angina, and functional class were independent of completeness of revascularization (p > 0.21). CONCLUSIONS: IMA grafting improved survival, angina, and functional class of octogenarians, but complete revascularization did not have a similar impact.

Aged↗
PubMed2001

Midterm results of complete arterial revascularization in more than 1,000 patients using an internal thoracic artery/radial artery T graft.

OBJECTIVE: To report the authors' 7-year experience with the internal thoracic artery/radial artery (ITA/RA) T graft as the only conduits for myocardial revascularization in two- and three-vessel disease. SUMMARY BACKGROUND DATA: One and two arterial conduits provide increasing survival benefit for coronary grafting and reduce the need for reintervention. Exclusive use of arterial conduits may provide further benefit. METHODS: From October 1993 to November 2000, 1,020 patients underwent complete arterial revascularization with the ITA/RA T graft. The authors focus on the 909 having initial bypass, with a mean age of 60 and 20% age 70 or older. The incidence of triple-vessel disease was 73%, female gender 28%, diabetes mellitus 27%, peripheral vascular disease 11%, cerebrovascular disease 10%, and chronic obstructive pulmonary disease 6%; ejection fraction was less than 35% in 11%. Perioperative data were collected prospectively. Follow-up information was obtained at a mean of 35.4 months (range 1-88) and was 95% complete. RESULTS: There were seven (0.08%) deaths within 30 days of surgery. The incidence of perioperative infarction was 3.3%, low cardiac output 2.7%, stroke 2.2%, reoperation for bleeding 3.8%, and deep sternal infection 0.8%. The actuarial survival rate was 90% at 5 years, freedom from infarction was 94%, freedom from catheterization was 83%, and freedom from reintervention (angioplasty or reoperation) was 93%. CONCLUSION: The ITA/RA T graft for complete arterial revascularization is associated with a low rate of perioperative death and complications and 5-year survival and freedom from reintervention values consistent with other revascularization strategies.

Aged↗
PubMed2000

Quality of life after aortic valve replacement at the age of >80 years.

BACKGROUND: The optimal management of aortic valve disease in patients >80 years old depends on functional outcome as well as operative risks and late survival. METHODS AND RESULTS: We retrospectively identified 133 patients (62 men, 71 women) aged 80 to 91 years (mean 84+/-3 years) who underwent aortic valve replacement alone or in combination with another procedure between January 1, 1993, and April 31, 1998. Demographics included hypertension 68%, diabetes mellitus 17%, and history of stroke 11%. Operative (30 day) mortality rate was 11%. Urgent or emergent surgery, aortic insufficiency, and perioperative stroke or renal dysfunction were risk factors for operative death by multivariable analysis. Intensive care unit and total hospital length of stay were prolonged at 6.2 and 14.7 days, respectively. Late follow-up between July 1, 1998, and November 1, 1999, was 98% complete. Actuarial survival at 1 and 5 years was 80% and 55%, respectively. Predictors of late mortality were preoperative or perioperative stroke, chronic obstructive pulmonary disease, aortic stenosis, and postoperative renal dysfunction. The mean New York Heart Association functional class for 65 long-term survivors improved from 3.1 to 1.7. Quality of life assessed with the Medical Outcomes Study Short Form-36 was comparable to that predicted for the general population >75 years old. CONCLUSIONS: Functional outcome after aortic valve replacement in patients >80 years old is excellent, the operative risk is acceptable, and the late survival rate is good. Surgery should not be withheld from the elderly on the basis of age alone.

Age Factors↗
PubMed2000

Options for repair of a bicuspid aortic valve and ascending aortic aneurysm.

BACKGROUND: Intrinsic abnormality of the aortic wall may explain the association of bicuspid aortic valves with ascending aortic aneurysms. Separate valve and graft repair of such lesions, rather than composite valve graft replacement, is more straightforward but leaves potentially abnormal sinuses behind. METHODS: Between January 1985 and January 1998, 45 patients underwent separate valve and graft (n = 27) or composite valve graft (n = 18) for an ascending aortic aneurysm and bicuspid aortic valve. Perioperative events and late results were compared. RESULTS: Patients undergoing separate valve and graft were older (mean age, 60 +/- 13 vs 42 +/- 12 years, p < 0.001) and were more likely to have purely stenotic (48% vs 6%, p = 0.003) than purely regurgitant (11% vs 72%, p < 0.001) disease. They were also more likely to require concomitant coronary artery bypass grafting (56% vs 6%, p = 0.001). There were no significant differences in operative risk and no known late complications related to recurrent aneurysms. CONCLUSIONS: Root replacement with a composite valve graft can be accomplished with low operative risk and is the first choice for repair of this lesion. Separate valve and graft repair, however, yields satisfactory early and late results and remains an acceptable option, especially when the coronary ostea are not displaced or when concomitant procedures must be performed.

Adult↗
PubMed2000

Radial artery harvest: comparison of ultrasonic dissection with standard technique.

BACKGROUND: The radial artery (RA) is used increasingly for myocardial revascularization. Having an ultrasonic dissector available in our unit, we began to use it for RA harvest with the impression that harvest spasm might be less for the new technique. METHODS: We compared RA harvest using standard techniques (21 RA) with ultrasonic dissection (41 RA) in which all branches were divided between clips with scissors in the former and bleeding branches were clipped in the latter. RESULTS: Harvest times were not different. Conventional technique used 74+/-18 (mean +/- standard deviation) clips versus 3.2+/-4.3 clips (p<0.001). In situ free flow was 17.2+/-20.7 mL/min for conventional technique versus 52.5+/-48.1 for ultrasonic (p<0.001). Free flow after the proximal anastomosis to the left internal thoracic artery was 38.5+/-60.4 mL/min for conventional technique and 50.7+/-29.6 for ultrasonic (p = 0.008). Free flow 10 minutes after intraluminal papaverine was 78.5+/-45.9 mL/min for usual technique versus 102.8+/-51.7 for ultrasonic (p = 0.016). No patient required reoperation for bleeding. CONCLUSIONS: Ultrasonic dissection of the RA is associated with decreased RA spasm, good hemostasis, no additional harvest time, and has become our standard technique.

Anastomosis, Surgical↗
PubMed2000

Selective use of extracorporeal membrane oxygenation is warranted after lung transplantation.

OBJECTIVES: Early allograft dysfunction after lung transplantation ranges from subclinical x-ray abnormalities to pulmonary edema, hypoxemia, hypercarbia, and pulmonary hypertension. Management may include extracorporeal circulation to allow recovery of the acute lung injury. We reviewed our experience with extracorporeal membrane oxygenation after lung transplantation to assess the utility of this therapy. METHODS: A retrospective chart review was performed. Single or bilateral lung transplantation was performed in 444 adults from July 1988 to July 1998. Twelve (2.7%) patients experienced allograft dysfunction severe enough to require extracorporeal membrane oxygenation after failure of conventional therapy, including sedation, paralysis, and inhaled nitric oxide. RESULTS: Seven of 12 patients requiring extracorporeal membrane oxygenation were discharged from the hospital. Mean and median times to extracorporeal membrane oxygenation support were 1.2 days and 0 days, respectively. Mean length of support was 4.2 days. Four patients died while receiving extracorporeal membrane oxygenation support. One patient was weaned from extracorporeal membrane oxygenation but died during the hospitalization. Two patients required acute retransplantation while receiving extracorporeal membrane oxygenation, and one survived to discharge. Three patients continued to receive extracorporeal membrane oxygenation support for more than 4 days, and all 3 died. All survivors had begun receiving extracorporeal membrane oxygenation support by post-transplantation day 1. Three of 7 patients discharged from the hospital died 12 months, 13 months, and 72 months after transplantation because of bronchiolitis obliterans syndrome (n = 2) or lymphoma (n = 1). Four patients are alive 2, 12, 25, and 54 months after transplantation. CONCLUSIONS: Extracorporeal membrane oxygenation provides effective therapy for acute post-transplantation lung dysfunction. The frequency and pattern of our extracorporeal membrane oxygenation use reflects bias toward early extracorporeal membrane oxygenation support for isolated graft failure in otherwise intact and uninfected recipients.

Adult↗
PubMed2000

Sinus nodal function and risk for atrial fibrillation after coronary artery bypass graft surgery.

BACKGROUND: Nonsurgical patients with sinus node dysfunction are at high risk for atrial tachyarrhythmias, but whether a similar relation exists for atrial fibrillation after coronary artery bypass graft surgery is not clear. The purpose of this study was to evaluate sinus nodal function before and after coronary artery bypass graft surgery and to evaluate its relation with the risk for postoperative atrial arrhythmias. METHODS: Sixty patients without complications having elective coronary artery bypass graft surgery underwent sinus nodal function testing by measurement of sinoatrial conduction time (SACT) and corrected sinus nodal recovery time (CSNRT). Patients were categorized based on whether postoperative atrial fibrillation developed. RESULTS: Twenty patients developed atrial fibrillation between postoperative days 1 through 3. For patients remaining in sinus rhythm (n = 40), sinoatrial conduction times were no different and corrected sinus nodal recovery times were shorter after surgery when compared with measurements obtained after anesthesia induction. Sinus node function test results before surgery were similar between the sinus rhythm and the atrial fibrillation groups. After surgery, patients who later developed atrial fibrillation had longer sinoatrial conduction times compared with the sinus rhythm group (P = 0.006), but corrected sinus nodal recover time was not different between these groups. A sinoatrial conduction time > 96 ms measured at this time point was associated with a 7.3-fold increased risk of postoperative atrial fibrillation (sensitivity, 62%; specificity, 81%; positive and negative predictive values, 56% and 85%, respectively; area under the receiver operator characteristic curve, 0.72). CONCLUSIONS: These data show that sinus nodal function is not adversely affected by uncomplicated coronary artery bypass surgery. Patients who later developed atrial fibrillation, however, had prolonged sinoatrial conduction immediately after surgery compared with patients remaining in sinus rhythm. These results suggest that injury to atrial conduction tissue at the time of surgery predisposes to postoperative atrial fibrillation and that assessment of sinoatrial conduction times could provide a means of identifying patients at high risk for postoperative atrial fibrillation.

Aged↗
PubMed2000

White matter injury in spinal cord ischemia: protection by AMPA/kainate glutamate receptor antagonism.

BACKGROUND AND PURPOSE: Spinal cord ischemia is a serious complication of surgery of the aorta. NMDA receptor activation secondary to ischemia-induced release of glutamate is a major mechanism of neuronal death in gray matter. White matter injury after ischemia results in long-tract dysfunction and disability. The AMPA/kainate receptor mechanism has recently been implicated in white matter injury. METHODS: We studied the effects of AMPA/kainate receptor blockade on ischemic white matter injury in a rat model of spinal cord ischemia. RESULTS: Intrathecal administration of an AMPA/kainate antagonist, 6-nitro-7-sulfamoyl-(f)-quinoxaline-2, 3-dione (NBQX), 1 hour before ischemia reduced locomotor deficit, based on the Basso-Beattie-Bresnahan scale (0=total paralysis; 21=normal) (sham: 21+/-0, n=3; saline: 3.7+/-4.5, n=7; NBQX: 12. 7+/-7.0, n=7, P<0.05) 6 weeks after ischemia. Gray matter damage and neuronal loss in the ventral horn were evident after ischemia, but no difference was noted between the saline and NBQX groups. The extent of white matter injury was quantitatively assessed, based on axonal counts, and was significantly less in the NBQX as compared with the saline group in the ventral (sham: 1063+/-44/200x200 microm, n=3; saline: 556+/-104, n=7; NBQX: 883+/-103, n=7), ventrolateral (sham: 1060+/-135, n=3; saline: 411+/-66, n=7; NBQX: 676+/-122, n=7), and corticospinal tract (sham: 3391+/-219, n=3; saline: 318+/-23, n=7; NBQX: 588+/-103, n=7) in the white matter on day 42. CONCLUSIONS: Results indicate severe white matter injury in the spinal cord after transient ischemia. NBQX, an AMPA/kainate receptor antagonist, reduced ischemia-induced white matter injury and improved locomotor function.

Animals↗
PubMed1999

Extended use of arterial conduits for myocardial revascularization.

Myocardial revascularization by means of surgical coronary artery bypass grafting has proven to provide reproducible and durable relief from the sequellae of coronary atherosclerosis. Despite the proven success of this operation, efforts are ongoing both to reduce the perioperative risks and morbidity, as well as to improve the long-term outcomes. The use of multiple arterial conduits is an example of the latter. This is based on the proven superior long-term patency of arterial grafts as compared with venous conduits. A remarkable wide variety of conduits and configurations are being explored currently. We outline our current thinking with regard to arterial grafting as the field now stands. The early results are encouraging, and suggest a significant improvement in long-term relief from angina pectoris and freedom from reintervention when multiple arterial conduits are employed.

Coronary Artery Bypass↗