Spinal cord injury following aortic arch replacement.

PURPOSE: Postoperative spinal cord injury is a devastating complication after aortic arch replacement. The purpose of this study was to determine the predictors of this complication. METHODS: A group of 254 consecutive patients undergoing aortic arch replacement via median sternotomy, with (n = 78) or without (n = 176) extended replacement of the upper descending aorta, were included in a risk analysis. The frozen elephant trunk technique was used in 46 patients. The patients' atherothrombotic lesions (extensive intimal thickening of > 4 mm) were identified from computed tomography images. RESULTS: Complete paraplegia (n = 7) and incomplete paraparesis (n = 4) occurred immediately after the operation (permanent spinal cord injury rate, 1.97%; transient spinal cord injury rate, 2.36%). A multivariable logistic regression analysis identified the use of the frozen elephant trunk technique (odds ratio 36.3), previous repair of thoracoabdominal aorta or descending aorta (odds ratio 29.4), proximal atherothrombotic aorta (odds ratio 9.6), chronic obstructive lung disease (odds ratio 7.1) and old age (odds ratio 1.1) as predictors of spinal cord injury (p < 0.0001, area under curve 0.93). CONCLUSIONS: Spinal cord injury occurs with a non-negligible incidence following aortic arch replacement. The full objective assessment of the morphology of the whole aorta and the recognition of the risk factors are mandatory.

Fatal airway obstruction due to a ball-valve clot with identical signs of tension pneumothorax.

Endo-tracheal tube obstruction due to an extensive blood clot is a recognized but very rare complication. A ball-valve obstruction in the airway could function as a check valve for the lung and thorax, resulting in tension pneumothorax-like abnormalities. A 47-year-old female patient had undergone implantation of a left ventricular assist device 3 weeks prior. On post-operative day 17, planned thoracentesis was performed for drainage of a pleural effusion. Despite the drainage, the patient's oxygenation did not improve, and emergency tracheal intubation was conducted. Subsequent computed tomography revealed bilateral pneumothorax. Two days later, the patient's trachea was extubated without complication, and a mini-tracheostomy tube was placed. Three hours later, reintubation was conducted due to progressive tachypnea. Although successful intubation was confirmed, ventilation became increasingly difficult and finally impossible. Marked increase in pulmonary artery and central venous pressures suggested progression of the previous tension pneumothorax. After emergency extracorporeal membrane oxygenation was initiated, fiberoptic bronchoscopy revealed the presence of a massive clot and ball-valve obstruction of the endotracheal tube. Two weeks later, the patient died due to severe hypoxic brain damage. Diagnosis of ball valve clot is not simple, but intensivists should consider this rare complication.

Bilateral versus single internal thoracic artery grafting in hemodialysis patients.

BACKGROUND: The use of the bilateral internal thoracic arteries (BITAs) during myocardial revascularization reportedly provides a survival benefit over using a single internal thoracic artery (SITA). However, the advantages in chronic hemodialysis patients, who generally have multiple comorbidities, is unclear. METHODS: Outcomes of chronic hemodialysis patients who underwent isolated coronary artery bypass grafting (CABG) using a SITA with additional saphenous vein grafts (SVGs) (n = 33) or BITAs (n = 30) for left-side revascularization were retrospectively reviewed. RESULTS: With the exception of the rate of diabetes mellitus (SITA vs. BITA: 84.8% vs. 50.0%; p = 0.003), the two groups showed similar patient characteristics. Using the off-pump technique, revascularization was completed without manipulation of the ascending aorta in 45.7% of patients in the BITA group, whereas all patients in the SITA group required aortic manipulation (p < 0.001). Of note, the incidence of extensive aortic calcification (>50% of ascending aorta circumference) was not uncommon (14.3%). The in-hospital mortality (3.0% vs. 0%, p = 0.336) and complication rates (including deep wound infection, re-exploration and stroke) were similar in both groups. The 5-year estimated survival rates for freedom from overall death in the SITA and BITA groups were 42.4% and. 57.4%, respectively (p = 0.202). CONCLUSIONS: BITA grafting was able to achieve revascularization with minimal manipulation of the diseased ascending aorta without increasing the complication rate. The long-term survival benefit of BITA grafting, however, was unclear in dialysis patients, especially because such patients have a relatively short life expectancy.

Superior mesenteric artery plasty for type A acute aortic dissection with visceral ischemia.

Treatment of visceral ischemia complicated with acute type A aortic dissection is controversial. We had two cases of acute type A aortic dissection complicated by superior mesenteric artery (SMA) ischemia and successfully treated them with direct SMA perfusion during central aortic repair followed by SMA plasty. The presented procedures can be an option to treat visceral ischemia with a standard operative theater and equipment.

Valve selection for the aortic position in dialysis patients.

BACKGROUND: Prosthetic valve selection in dialysis patients remains controversial because of the limited data available. This study aimed to clarify late clinical outcomes and discuss strategies for optimal valve selection in dialysis patients. METHODS: We retrospectively analyzed the data obtained from 406 consecutive patients who underwent aortic valve replacement between 1995 and 2010. We compared valve-related outcomes among 89 dialysis and 317 nondialysis patients. We selected bioprostheses for all patients older than 65 to 70 years, irrespective of the renal function. RESULTS: Dialysis was found to be a significant risk factor for bleeding events (hazard ratio, 3.98; 95% confidence interval, 2.51 to 6.30; p < 0.001), however, no significant differences were observed according to the type of prosthesis. The overall survival was significantly worse in the dialysis patients (63% versus 85% at 5 years; p < 0.001), and freedom from structural valve deterioration was also lower in the dialysis patients (82% versus 100% at 5 years; p < 0.001). Among the dialysis patients, an advanced age (≥ 70 years; hazard ratio, 3.53; p = 0.011), diabetes mellitus (hazard ratio, 2.48; p = 0.041), and concomitant coronary artery bypass grafting (hazard ratio, 1.99; p = 0.071) were independent predictors for late death based on a multivariate analysis. CONCLUSIONS: Our valve selection criteria in dialysis patients, which are the same as the current practice guidelines for nondialysis patients, are acceptable. Bioprostheses can be considered in all dialysis patients with diabetes or coronary artery disease.

Clinical validation of coronary artery flow through an intracoronary shunt during off-pump coronary artery bypass grafting.

OBJECTIVES: Intracoronary shunts have been developed for a bloodless field and preserved forward flow preventing ischemia during off-pump coronary artery bypass (OPCAB) surgery. However, reports directly measuring the forward flow through the shunt in clinical settings are lacking. METHODS: Using a 7.5-MHz Doppler probe, we investigated the coronary flow through a 1.5-mm shunt inserted into the left anterior descending artery (LAD) for anastomosis with the internal thoracic artery during OPCAB in 30 consecutive patients. The following Doppler flow parameters were obtained before and after shunting: peak velocity, mean velocity, time-velocity integral, and flow. RESULTS: No patients developed significant electrocardiographic changes and the peak value of postoperative myocardial band of creatine kinase was 17 ± 16 IU/L. All Doppler flow parameters of the LAD decreased significantly after shunting; peal velocity: 71.3 ± 34.6 cm/second to 54.5 ± 25.3 cm/second (-24% ± 27%), mean velocity: 33.3 ± 18.3 cm/second to 26.3 ± 14.0 cm/second (-21% ± 23%), and time-velocity integral: 28.7 ± 12.1 cm to 19.0 ± 7.1 cm (-28% ± 14%), and flow: 38.7 ± 16.8 mL/minute to 25.0 ± 9.5 mL/minute (-31% ± 13%) (P < .01). CONCLUSIONS: The LAD flow is preserved at least 50% through a 1.5-mm intracoronary shunt, although the flow pattern was attenuated, during OPCAB anastomosis. The Doppler evaluation of the coronary artery flow before and after shunting is useful to justify the protective use of the shunt on myocardial perfusion during OPCAB.

Effects of the side of arteriovenous fistula on outcomes after coronary artery bypass surgery in hemodialysis-dependent patients.

OBJECTIVE: The aim of the study was to determine whether using the in situ internal thoracic artery (ITA) graft ipsilateral to the arteriovenous fistula adversely affects the outcomes after isolated coronary artery bypass grafting (CABG) in the dialysis-dependent patients to answer the concerns of a possible steal and consequent myocardial ischemia. METHODS: We categorized 155 dialysis patients undergoing isolated CABG between January 1993 and December 2011 into 108 patients (70%, ipsilateral group) whose left anterior descending artery (LAD) was revascularized with the ITA ipsilateral to the arteriovenous fistula and 47 patients (contralateral group) whose LAD was grafted with the ITA opposite to the fistula, to compare their early and late outcomes. RESULTS: While 94% of the ipsilateral group had left fistula, 55% of the contralateral group had left fistulas. The LAD was grafted with the left ITA in 94% of the ipsilateral group, whereas it was grafted with left (49%) or right (51%) ITAs in the contralateral group. There was no significant difference in hospital mortality between the groups (ipsilateral 10.2% vs contralateral 10.6%). After follow-up for 55 ± 42 months, the overall survival (ipsilateral 58% vs contralateral 65% at 5 years) and cardiac event-free rates (ipsilateral 74% vs contralateral 68% at 5 years) were also similar between the groups by log-rank tests (P = .90 and P = .07). CONCLUSIONS: Revascularization of the LAD using the in situ ITA graft ipsilateral to the arteriovenous fistula increases neither the operative mortality nor the risks of late death and cardiac events after isolated CABG in dialysis patients.

Recent risk factors for open surgical mortality in patients with ruptured abdominal aortic aneurysm.

AIM: We examined recent relevant prognostic factors for the outcome of open surgical treatment of ruptured abdominal aortic aneurysm. METHODS: Between 2006 and 2012, 35 patients received emergency open surgical treatment for ruptured abdominal aortic aneurysm at our institute. We reviewed ambulance activity logs and clinical records of 34 infrarenal ruptured abdominal aortic aneurysm patients retrospectively. Univariate and multivariate logistic regression analyses were carried out to identify risk factors for surgical outcomes. RESULTS: Eight patients died during surgery or within a few hours following surgery completion. Through univariate analysis, body mass index, serum lactate level, arterial blood pH, base excess, platelet count, prothrombin time-international normalized ratio, activated partial thromboplastin time, type of ruptured aneurysm, response to i.v. fluid resuscitation within 2,000 mL in the initial therapy, and volume of blood loss during surgery were detected to be significant variants. Multivariate logistic regression analysis revealed the patients who were hemodynamically stabilized after primary volume loading had a 13.2 times higher possibility of survival. Body mass index, high serum lactate level, and volume of blood loss were also found to be independent risk factors of mortality. CONCLUSION: The risk factors of open surgical ruptured abdominal aortic aneurysm repair, body mass index, lactate level, volume of intraoperative blood loss, and response to initial 2,000 mL fluid resuscitation were correlated to survival.

Predictors for early and late outcomes after coronary artery bypass grafting in hemodialysis patients.

BACKGROUND: Markedly higher hospital and long-term mortality after coronary artery bypass grafting (CABG) have been reported in hemodialysis (HD)-dependent patients. We tried to identify the predictors for short-term and long-term outcomes after CABG, which have not been well studied. METHODS: Between 1993 and 2010, 152 patients undergoing HD (117 men; HD duration of 8.7±8.0 years) underwent isolated CABG. Our strategies included use of a single internal thoracic artery (ITA) in patients with diabetes mellitus (DM), bilateral ITAs in patients without DM, and possible avoidance of cardiopulmonary bypass (CPB) after 2003. RESULTS: Thirty-six percent of patients underwent conventional CABG: 20% had on-pump beating heart procedures and 44% had off-pump procedures, with 2.8±1.0 anastomoses. Hospital mortality was 10.6% with improvement to 6.8% after 2003. Predictors for hospital death were left ventricular ejection fraction (LVEF) less than 0.40 (p=0.042), use of CPB (p=0.046), and postoperative need for continuous hemofiltration (p=0.037). After follow-up of 49±42 months, the overall survival rates were 76.9%, 60.0%, 43.9%, and 36.2% and the cardiac events-free rates were 77.0%, 70.1%, 55.9%, and 44.8% at 3, 5, 8, and 10 years, respectively, in the Kaplan-Meier model. A multivariate Cox proportional hazard model identified age older than 63 years (p=0.014), DM (p=0.036), and peripheral artery disease (PAD) (p=0.044) as predictors for late death, and DM (p=0.038) and LVEF less than 0.40 (p=0.027) as predictors for late cardiac events. CONCLUSIONS: Although early outcomes have been improved by off-pump techniques, late outcomes are not satisfactory in patients who rely on HD and undergo CABG. To improve late outcomes we may need aggressive management of DM, PAD, and low LVEF in those patients.

Long-term size follow-up of knitted Dacron grafts (Gelseal™) used in the ascending aorta.

There is limited information about the size change of a knitted Dacron graft (Gelseal™) used in the thoracic aorta. We evaluated the diameters of the Gelseal™ grafts at a long-term follow-up for 3.7 ± 1.3 years (1-5.9 years; median, 4.0 years), which were used for replacement of the ascending aorta in 59 patients with acute aortic dissection. The early and late dilatation rates (LDRs) of the prosthetic grafts were calculated retrospectively based on the graft diameter at the level equivalent to the ascending aorta on the pre-discharge computed tomography (CT) scans and follow-up CT scans performed every year after surgery. Immediately after surgery (15 ± 7 days), the early dilatation of the Gelseal™ grafts was 26.0 ± 6.0% with significant correlations with the number of post-operative days (R = 0.500, P = 0.003). At the follow-up for 3.7 ± 1.3 years, the LDR was 10.5 ± 6.6%, which was also significantly correlated with the number of the post-operative years (R = 0.608, P = 0.001). Linear regression analysis indicated that the annual dilatation rate was ≈ 3.23%. During the follow-up, we have experienced no redo surgery due to graft fracture or false aneurysm formation at the anastomosis sites associated with the graft dilatation. In conclusion, the Gelseal™ graft used in the ascending aorta demonstrates a small but continuous increase in the diameter, up to 5 years after implantation, without any adverse events.

Can we predict the site of entry tear by computed tomography in patients with acute type a aortic dissection?

BACKGROUND: In patients with acute type A aortic dissection (AAD), localization of the primary entry tear to be excluded is of major importance for intervention. HYPOTHESIS: There are reliable indirect computed tomography (CT) findings to predict the entry site. METHODS: In 83 patients with type A AAD whose primary entry tears were identified surgically between 2003 and 2009, we retrospectively examined the diagnostic CT scans regarding pericardial effusion, the largest short-axial diameter of the aorta, widths of true and false lumens, and false lumen thrombosis at 6 levels of thoracic aorta from the aortic root to the descending aorta. RESULTS: The primary entry sites identified intraoperatively were proximal ascending in 21 patients, middle ascending in 21, distal ascending in 21, arch in 17, and descending or unknown in 16. The multivariate logistic analysis revealed that pericardial effusion (odds ratio [OR]: 2.2, 95% confidence interval [CI]: 1.2-3.4, P < 0.001) and dilated ascending aorta (OR: 1.6, 95% CI: 1.1-2.4, P = 0.012) were the significant CT findings to predict the entry tear in the ascending aorta. It also revealed that the significant CT finding to predict the entry tear distal to the aortic arch was nonthrombosed false lumen in the descending aorta (OR: 1.2, 95% CI: 1.1-2.1, P = 0.048). CONCLUSIONS: We can predict the primary entry site by the preoperative CT findings in patients with type A AAD, considering pericardial effusion, aortic diameter, widths of true and false lumens, and false lumen thrombosis at different anatomic levels.

Simplified management of hemodialysis-dependent patients undergoing cardiac surgery.

BACKGROUND: The mortality and morbidity rates are high after cardiac surgery in hemodialysis (HD)-dependent patients. To improve their outcomes, optimal perioperative managements should be discussed. METHODS: A retrospective analysis of 245 HD patients who underwent cardiac surgery between 1994 and 2007 was conducted. The basic management strategies were (1) low-potassium HD for 2 days before surgery, (2) only hemofiltration during cardiopulmonary bypass, and (3) start of regular intermittent HD on the first postoperative day. Continuous venovenous hemodiafiltration was applied only for patients with hemodynamic instability. RESULTS: The causes of renal failure included diabetic (n = 89, 36%), glomerulonephritis (n = 49, 20%), and unknown (n = 75, 31%). The history of HD was 9.7 +/- 7.6 years. The operative procedures included coronary (n = 135), valve (n = 103), and others. The amount of intraoperative ultrafiltration was 6,123 +/- 324 mL during cardiopulmonary bypass for 197 +/- 67 minutes. Two hundred eight patients (85%) were managed with only intermittent HD, whereas 36 patients (15%) needed continuous venovenous hemodiafiltration. The use of continuous venovenous hemodiafiltration significantly declined during the year (26% before 2003 and 3% after 2003; p < 0.001). The amount of fluid removal on the first postoperative day was 1,297 +/- 81 mL. The hospital mortality was 9.7% with the causes including infection (n = 11), cardiac events (n = 6), gastrointestinal events (n = 5), and stroke (n = 2). A multivariate logistic regression analysis revealed that selection of intermittent HD or continuous venovenous hemodiafiltration was not related to the hospital mortality. CONCLUSIONS: Simplified management only with intermittent HD can be safely performed in most HD-dependent patients undergoing cardiac surgery.