Influence of clinical presentation on the outcome of acute B aortic dissection: evidences from IRAD.

AIM: In-hospital outcome of acute type B dissection (ABAD) is strongly related to preoperative aortic conditions. In order to clarify the influence of the clinical presentation on the outcome, we analyzed the patients of the International Registry of Acute Aortic Dissection (IRAD). All patients affected by complicated ABAD, enrolled in the IRAD from 1996-2004, were included. Complications were defined as the presence of shock, periaortic hematoma, spinal cord ischemia, preoperative mesenteric ischemia/infarction, acute renal failure, limb ischemia, recurrent pain, refractory pain or refractory hypertension (group I). All other patients were categorized as uncomplicated (group II). A comprehensive analysis was performed of all clinical variables in relation to in-hospital outcome. RESULTS: The overall in-hospital mortality among 550 patients was 12.4%. Mortality in group I (250 patients) was 20.0 %, compared to 6.1% in group II (300 patients) (P<0.001). Univariate predictors of ABAD complications were Marfan syndrome, abrupt onset of pain, migrating pain, any focal neurological deficits, need for higher number of diagnostic examinations and use of magnetic resonance and/or aortogram, abdominal vessels involvement at aortogram, larger descending aortic diameter, especially >6 cm, pleural effusion, and widened mediastinum on chest X-ray. Univariate predictors of a non complicated status were normal chest X-ray and medical management. In group I, in-hospital mortality following surgical and endovascular intervention were 28.6% and 10.1% (P=0.006), respectively. Independent predictors of overall in-hospital mortality included age >70 years, female gender, ECG showing ischemia, preoperative acute renal failure, preoperative limb ischemia, periaortic hematoma, and surgical management. The only independent variable protective for mortality was magnetic resonance as diagnostic test. CONCLUSION: ABAD is a heterogeneous disease that produces dissimilar clinical subsets, each of which can have specific clinical signs, management and in-hospital results. In IRAD ABAD uncomplicated patients, medical therapy was associated with best hospital outcome, while endovascular interventions were associated with better results than surgery when invasive treatments were required. Although selection bias may be possible, and irrespective of treatments, knowledge of significant risk factors for mortality may contribute to a better management and a more defined risk-assessment in patients affected by ABAD.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

A randomized clinical trial of continuous aspiration of subglottic secretions in cardiac surgery patients.

STUDY OBJECTIVES: To determine whether the application of continuous aspiration of subglottic secretions (CASS) is associated with a decreased incidence of ventilator-associated pneumonia (VAP). DESIGN: Prospective clinical trial. SETTING: Cardiothoracic ICU (CTICU) of Barnes-Jewish Hospital, St. Louis, a university-affiliated teaching hospital. PATIENTS: Three hundred forty-three patients undergoing cardiac surgery and requiring mechanical ventilation in the CTICU. INTERVENTIONS: Patients were assigned to receive either CASS, using a specially designed endotracheal tube (Hi-Lo Evac; Mallinckrodt Inc; Athlone, Ireland), or routine postoperative medical care without CASS. RESULTS: One hundred sixty patients were assigned to receive CASS, and 183 were assigned to receive routine postoperative medical care without CASS. The two groups were similar at the time of randomization with regard to demographic characteristics, surgical procedures performed, and severity of illness. Risk factors for the development of VAP were also similar during the study period for both treatment groups. VAP was seen in 8 patients (5.0%) receiving CASS and in 15 patients (8. 2%) receiving routine postoperative medical care without CASS (relative risk, 0.61%; 95% confidence interval, 0.27 to 1.40; p = 0. 238). Episodes of VAP occurred statistically later among patients receiving CASS ([mean +/- SD] 5.6 +/- 2.3 days) than among patients who did not receive CASS (2.9 +/- 1.2 days); (p = 0.006). No statistically significant differences for hospital mortality, overall duration of mechanical ventilation, lengths of stay in the hospital or CTICU, or acquired organ system derangements were found between the two treatment groups. No complications related to CASS were observed in the intervention group. CONCLUSIONS: Our findings suggest that CASS can be safely administered to patients undergoing cardiac surgery. The occurrence of VAP can be significantly delayed among patients undergoing cardiac surgery using this simple-to-apply technique.

Reappraisal of coronary endarterectomy for the treatment of diffuse coronary artery disease.

BACKGROUND: The development of new technologies such as transmyocardial laser revascularization and, more recently, local delivery of angiogenic growth factors has refocused attention on the surgical management of diffuse coronary artery disease. In some cases, coronary endarterectomy is also technically feasible. To facilitate decision-making among these options, we reviewed our experience with coronary endarterectomy to determine the results to be expected with this more traditional approach. METHODS: A search of our computerized database identified 7,096 patients undergoing myocardial revascularization between January 1, 1986 and March 30, 1997, of whom 177 (2.3%) underwent endarterectomy of at least one coronary artery. Perioperative events were derived from the database. Follow-up information was obtained from patients at 3 months to 11.5 years (mean = 55.7 +/- 38.8 months) after surgery. RESULTS: Endarterectomy was performed on the right coronary artery (RCA) system in 100 patients, the left anterior descending (LAD) system in 52, the circumflex system in 18, and in multiple distributions in 7. The 30-day mortality was 7% for RCA, 0% for LAD, 17% for circumflex, and 14% for multi-system endarterectomy (p = 0.20). There were no statistically significant differences in perioperative myocardial infarction or ventricular dysrhythmia between these groups. Actuarial survival at 5 years was 76% for patients undergoing RCA endarterectomy and 75% for left sided (LAD or circumflex) endarterectomy (p = 0.91). At late follow-up, 74% (86/117) of survivors were angina-free, 6% (7/117) had undergone subsequent angioplasty, and 3% (4/117) had undergone subsequent surgery. CONCLUSIONS: Coronary endarterectomy can be accomplished with acceptable operative risk and good long-term results, even when applied in a highly selective manner. The results of novel therapies for diffuse coronary artery disease should be considered in the context of those achievable with more traditional approaches.