Yoshihiro Toshima

Risk stratification analysis of operative mortality in heart and thoracic aorta surgery: comparison between Parsonnet and EuroSCORE additive model

OBJECTIVE Our purpose was to compare the performance of risk stratification model between Parsonnet and European System for Cardiac Operative Risk Evaluation (EuroSCORE) in our patient database. METHODS From August 1994 to December 2000, 803 consecutive patients have undergone heart and thoracic aorta surgery using cardiopulmonary bypass and scored according to Parsonnet and EuroSCORE algorithm. The population was divided into five clinically relevant risk categories. We compared correlation of predicted mortality and observed mortality between these two models. Score validity was assessed by calculating the area under the receiver operating characteristic (ROC) curve. RESULTS Overall hospital mortality was 4.5%. In Parsonnet model, predicted mortality was 2.4% for 0-4% risk, 6.7% for 5-9% risk, 12% for 10-14% risk, 17% for 15-19% risk, 25% for 20% plus risk, and 10.4% for overall patients. Observed mortality was 2.4, 0.4, 5.9, 8.7, 11, and 4.5%, respectively. The thoracic aorta and valve cohort indicated poor correlation between predicted and observed mortality compared to coronary cohort. In the EuroSCORE model, predicted mortality was 1.4% for 0-2% risk, 4.0% for 3-5% risk, 6.7% for 6-8% risk, 9.7% for 9-11% risk, 13% for 12% plus risk, and 5.3% for overall patients. Actual mortality was 0, 1.5, 6.8, 11, 21, and 4.5%, respectively. Each of the thoracic aorta, valve, and coronary cohort indicated good correlation between predicted and observed mortality. Areas under the ROC curves were 0.72 in Parsonnet and 0.82 in EuroSCORE. CONCLUSIONS The EuroSCORE additive model yielded good predictive value for hospital mortality of Japanese patients undergoing not only cardiac but also thoracic aortic surgery.

Comparative study of cell saver and ultrafiltration nontransfusion in cardiac surgery

Hemoconcentration for the establishment of no-donor blood transfusion in open heart surgery was assessed in regard to both the saving of protein and platelets and the exclusion of free hemoglobin. Two different types of hemoconcentrator were compared: the ultrafilter (group I, 6 patients) and the Cell Saver (group II, 6 patients). The total serum protein level, expressed as the percent recovery of the preoperative value, after hemoconcentration was significantly higher in group I (group I versus group II: total serum protein, 118% versus 87% [p less than 0.05]; fibrinogen, 77% versus 50% [p less than 0.01]; immunoglobulin, 83% versus 60% [p less than 0.01]). The platelets also seemed to be well preserved after hemoconcentration in group I. Although the exclusion of free hemoglobin from plasma was inferior in group I compared with group II, the postoperative plasma free hemoglobin level did not increase in group I. We conclude that use of the Cell Saver in nontransfusion cardiopulmonary bypass might cause a severe depletion of various proteins and that the ultrafilter is both safer and more useful if employed routinely.

Postoperative cardiac rhythms with superior septal approach and lateral approach to the mitral valve

BACKGROUND The superior-septal approach provides an excellent view of the mitral valve and therefore has received considerable interest. However, the safety of this approach is controversial because it requires division of the sinus node artery in most cases. METHODS Postoperative cardiac rhythms were analyzed in 152 consecutive patients who underwent mitral valve procedures between January 1992 and February 1995 with a conventional right lateral left atriotomy (group 1, n = 69) or the superior-septal approach (group 2, n = 83). Follow-up ranged from 2 to 38 months, and the mean follow-up was 16.1 months in group 1 and 13.8 months in group 2. RESULTS The mortality rate was similar in the two groups (1.4% in group 1 and 1.2% in group 2), and the causes of death were not related to the left atriotomy. At discharge, 96% of the patients in group 1 who were in sinus rhythm preoperatively and 78% of those in group 2 remained in sinus rhythm. At the last follow-up, 88% of these patients in group 1 and 83% in group 2 remained in sinus rhythm. Among the patients in atrial fibrillation or junctional rhythm before operation, 12% in group 1 and 11% in group 2 had regained sinus rhythm at the last follow-up. There were no significant differences in these values. CONCLUSIONS Although the incidence of dysrhythmias was higher with the superior-septal approach in the early postoperative period, this approach provides an excellent operative view of the mitral valve and similar results in terms of late postoperative cardiac rhythms as the right lateral left atriotomy.

Simplified Manouguian's aortic annular enlargement for aortic valve replacement

A simplified Manouguians aortic annular enlargement for aortic valve replacement with prosthetic valve was performed in a patient with severe aortic stenosis and mild regurgitation by preserving both the anterior mitral leaflet and the left atrial roof intact. This method minimized the operative risk by avoiding injury to the mitral valve, while inserting a possibly two-size-larger prosthetic valve. The inserted prosthetic valve was positioned parallel to the original aortic valve. Moreover, the incision from the top of the commissure between the noncoronary cusp and left coronary cusp through the interventricular fibrous trigone appears to be easily extended into the exact center of the anterior mitral leaflet if further enlargement is required.

Stroke in thoracic aortic surgery: outcome and risk factors.

The risk factors and the outcome of stroke in thoracic aortic surgery were studied in 127 patients (86 males, 41 females), aged 18 to 84 years (mean, 64 years), operated on between September 1994 and December 2000. There were 29 operations on the ascending aorta, 63 arch, 29 descending, 5 thoracoabdominal, and 1 extraanatomical bypass. Perioperative stroke occurred in 15 patients (12%). The risk factors for stroke were identified as preexisting chronic renal failure and femoral arterial cannulation. Hospital death occurred in 4 of the 15 cases (27%) of stroke and 7 of the 112 cases (6%) without stroke (p < 0.05). There were 18 late deaths during a mean follow-up period of 3.2 years (range, 1 month to 7.2 years). The 3-year survival rates were 43 ± 14% in the stroke patients and 85 ± 4% in the other patients. Actuarial survival, including during hospitalization, was lower in the stroke patients than in the other patients not only among those 70 years or older but also among all the patients (both p < 0.0001). Stroke occurring in thoracic aortic surgery is thus an important risk factor for early and late mortality, particularly in patients 70 years or older.

The Protective Effects of Trimetazidine on Normothermic Ischemic Myocardium in Rats

The protective effects of trimetazidine on postischemic cardiac function were studied using isolated working rat heart preparations in which global ischemia had been induced with normothermic cardioplegia. After 30 minutes of reperfusion, following a 25 minutes period of ischemia, the addition of 10−6 M or 10−5 M trimetazidine to the cardioplegic solution significantly increased the per cent recovery of the cardiac output: from 54.8±4.1 per cent in the control group to 81.0±3.2 per cent (p<0.01) and 79.6±4.0 per cent (p<0.01), respectively, although lower (10−7 M) or higher (10−4 M) doses of the drug failed to result in any change. 10−5 M trimetazidine also produced a significantly greater recovery of both the postischemic aortic flow: from 47.8±4.9 per cent to 72.2±3.8 per cent (p<0.01) and the coronary flow: from 80.6±2.9 per cent to 105.2±6.3 per cent (p<0.002). However, trimetazidine did not influence the recovery of either aortic pressure or heart rate. These results suggest that trimetazidine does give some protection to the heart during ischemia and reperfusion.

Left ventricular—Coronary sinus shunt through a septal aneurysm after mitral valve re-replacement

We describe a case in which a left ventricular-coronary sinus communication through a dissecting ventricular septal aneurysm developed after a redo mitral valve replacement. The outlet orifice of the communication was located in the side wall of the ostium of the coronary sinus. Both the communication and the aneurysm were successfully dealt with by performing a right atriotomy and by opening the aneurysm from its outlet orifice.

Emergency surgery results in life-threatening thoracic aortic disease

OBJECTIVE Emergency surgery for thoracic aortic aneurysm continues to involve high mortality. We review our experience in emergency surgery for life-threatening thoracic aortic disease. METHODS Between September 1994 and June 2000, 65 consecutive patients--38 men and 27 women aged 18 to 84 years (mean: 64.3 years)--underwent emergency surgery for thoracic aortic disease. Of these, 40 (61%) were treated for acute type A dissection, 16 (25%) for aortic rupture, and 9 (14%) for impending aneurysmal rupture. Ascending aorta repair was conducted in 21, aortic arch repair in 30, distal arch repair in 2, descending aorta repair in 9, and thoracoabdominal aorta repair in 3. Of the 65, 42 were under 70 years old and 23 were 70 years of age and older. RESULTS Overall, 8 (12%) died in the hospital--3 (7.5%) of acute type A dissection, 3 (19%) of ruptured aneurysm, and 2 (22%) of impending rupture. Of these, 3 (7.1%) were younger than 70 years and 5 (22%) 70 years and older. The following perioperative factors significantly influenced hospital mortality: pump time (p = 0.019), postoperative severe cardiac failure (p = 0.006), postoperative respiratory failure (p = 0.045), and postoperative acute renal failure (p = 0.0007). Of the 57 survivors followed up for an average of 2.8 years (1 month to 6 years), 3-year survival was 73% overall--88% in patients younger than 70 years and 38% in those 70 years and older (p = 0.0004). Seven of the 9 patients suffering strokes during surgery died in the hospital (2) or after discharge (5). Overall hospital and late deaths involved 2 of 4 patients younger than 70 years and all of 5 patients 70 years and older. CONCLUSION The majority of patients undergoing emergency surgery for life-threatening thoracic aortic disease can undergo graft replacement with acceptable mortality, morbidity, and late survival, but early and late mortality for patients older than 70 remains extremely high.

Outcome of cardiac and thoracic aortic operation in patients over 80 years old.

A retrospective analysis was performed to determine the early outcome of cardiac and thoracic aortic surgery in patients over 80 years old. Between 1994 and 2000, 41 octogenarians (mean age, 82.6 ± 2.5 years) underwent coronary artery bypass grafting (25), valve surgery (8), thoracic aortic aneurysm repair (7), or combined valve and bypass surgery (1). Overall hospital mortality was 9.8%. Mortality rates for specific procedures were 12% for coronary bypass, 0% for valve surgery, and 14% for thoracic aortic aneurysm repair. Major postoperative complications affected 27% of patients and included severe low cardiac output, respiratory failure, and acute renal failure, with a low incidence of perioperative stroke (2.4%). Cardiac and thoracic aortic operations can be performed with acceptable mortality and morbidity when appropriately applied in selected octogenarians.

Risk stratification analysis of operative mortality in coronary artery bypass surgery

OBJECTIVE We assessed the operative mortality of coronary artery bypass grafting (CABG) surgery using risk stratification. METHODS In 294 consecutive patients who underwent CABG with or without concomitant surgery from August 1994 to December 1999, we compared operative mortality calculated conventionally and by risk stratification. Scores for each patient were calculated using the Parsonnet additive model and stratified based on the probability of operative mortality. RESULTS Overall crude hospital mortality was 4.8%-4.0% among patients younger than 80 years and 14% among those 80 years of age or older (p = 0.0692). Hospital mortality was 12% in urgent/emergency surgery, and 1.5% in elective surgery (p < 0.0002), and 4.5% in CABG alone and 7.4% in CABG with concomitant surgery (p = 0.3763), and 25% in patients receiving vein grafts only and 3.0% in those receiving at least 1 artery graft (p = 0.0003). Overall patient distribution was 32% good, 20% fair, 20% poor, 11% high-risk, and 16% extremely high-risk. Predicted mortality was 2.2% for patients who were a good risk, 6.7% for fair-risk, 12% for poor-risk, 16% for high-risk, and 25% for extremely high-risk patients. Actual operative mortality was 1.0% for good-risk, 0% for fair-risk, 3.4% for poor-risk, 6.3% for high-risk, and 18% for extremely high-risk patients, making actual mortality significantly lower than that predicted. CONCLUSION Comparing predicted mortality and actual mortality enabled us to objectively calculate operative results and assess operative quality.