Incidence Of Low Cardiac Output Research Articles

Myocardial Priority Promotes Cardiovascular Recovery for Acute Type A Aortic Dissection Combined with Coronary Artery Disease Undergoing Aortic Arch Surgery.

The optimal surgical strategy for acute type A aortic dissection (ATAAD) with coronary artery disease (CAD) remains unclear. The goal of this study was to investigate the cardiovascular protective effects of the myocardial priority (MP) strategy or traditional selective cerebral perfusion (SCP) in ATAAD with CAD. A total of 214 adults were analyzed retrospectively, of which 80 underwent the MP strategy intraoperatively. Seventy-nine pairs were propensity-score-matched and divided into SCP and MP groups. The follow-up period ranged from 6 to 36 months. The MP group had a significantly shorter myocardial ischemic time, higher perfusion flow, higher radial artery pressure, and lower incidence of NIRS decrease >20% of the base value, but a longer lower limb circulatory arrest and bypass time than the SCP group. Although similar adverse cardiac and cerebrovascular events were observed in both groups, a shorter posthospital stay, less blood loss and transfusion, higher postoperative hemoglobin, lower creatinine, and higher PaO2/FiO2 were observed in the MP group. Subgroup analysis showed that when the TIMI Risk Score was <4, the MP group had a lower incidence of low cardiac output and lower postoperative cTnI level. The follow-up patients had similar morbidities between the two groups. The novel MP strategy is associated with a shortened myocardial ischemic time, better maintained perfusion of vital organs, and postoperative recovery after surgery for ATAAD combined with non-severe CAD.

Effect of perioperative use of oral triidothyronine for infants undergoing complex congenital cardiac surgeries under cardiopulmonary bypass: A double-blinded randomised controlled study.

ABSTRACTBackground:Thyroid hormone metabolism disrupts after cardiopulmonary bypass both in adults and pediatric patients. This is known as Euthyroid sick syndrome, and it is more evident in pediatric patients who were undergoing complex cardiac surgeries compared to adults. This decrease in serum T3 levels increases the incidence of low cardiac output, requirement of inotropes, prolonged mechanical ventilation, and prolonged intensive care unit (ICU) stay.Aims and Objectives:The primary objective was to compare the mean Vasoactive-inotropic score (VIS) at 72 hours postoperatively between T3 and Placebo groups.Materials and Methods:One hundred patients were screened, and 88 patients were included in the study. Triidothyronine 1 mic/kg 10 doses 8th hourly was given orally postoperatively to cases and sugar sachets to controls. The blood samples for analysis of FT3, FT4, and TSH were taken every 24 hours postoperatively, and baseline values were taken after induction. Mean VIS scores, ejection Fraction (EF), Left ventricular outflow tract velocity time integral (LVOT VTi), hemodynamics and partial pressure of oxygen/ fraction of inspired oxygen(PaO2/FiO2) were recorded daily.Results:The Mean VIS scores at 72 Hours postoperatively were significantly less in the T3 group (5.49 ± 6.2) compared to the Placebo group (13.6 ± 11.7). The PaO2/FiO2 ratios were comparatively more in the T3 group than the Placebo group. The serum levels of FT3 FT4 were significantly higher in the T3-supplemented group than the Placebo group. The VIS scores were significantly lower from 48 hours postoperatively in children < 6 months of age.Conclusion:In this study, we observed that supplementing T3 postoperatively decreases the ionotropic requirement from 72 hours postoperatively. This is more useful in children <6 months of age undergoing complex cardiac surgeries.

Adult tetralogy repair: factors affecting early outcome in the current era.

Background The benefits of surgical correction of adult tetralogy of Fallot are well known. The current recommendation is for total correction regardless of age. This study analyzed perioperative factors affecting early outcome after corrective surgery in adulthood in the current era. Methods This was a retrospective chart review of 40 consecutive patients over 18 years of age who underwent total correction of tetralogy of Fallot from September 2006 to June 2013. Patients with pulmonary atresia and absent pulmonary valve were excluded. The mean age at surgery was 26.60 ± 8.69 years (range 18–49 years). Results The mean intensive care unit stay was 3.30 ± 2.29 days (range 0.75–12 days) and hospital stay was 9.97 ± 3.39 days (range 7–22 days). Mortality was 5% (2/40). Multiple parameters indicating immediate postoperative outcomes and their relationships to selected pre-, intra-, and postoperative factors were analyzed. Multivariate analysis showed that postoperative right ventricular dysfunction had a significant influence on mortality ( p &lt; 0.001) and hospital stay ( p = 0.01). Performing zero-balance ultrafiltration decreased the need for renal replacement therapy ( p = 0.034), duration of ventilation ( p = 0.009), incidence of low cardiac output ( p = 0.006), intensive care unit stay ( p = 0.01), and hospital stay ( p = 0.009). Conclusions Total correction of tetralogy of Fallot is a safe option for presentations as late as adulthood. The protective effect of zero-balance ultrafiltration on postoperative morbidity needs to be reassessed in larger studies.

Comparison of effects of propofol versus sevoflurane for patients undergoing cardiopulmonary bypass cardiac surgery.

Objective:To compare the effects of propofol versus sevoflurane on the outcomes of patients undergoing cardiac surgery with cardiopulmonary bypass (CPB).Methods:A total of 110 patients undergoing cardiac surgery with CPB in our hospital from January 2015 to June 2017 were randomly divided into 2 groups (n=55): Group A, in which anesthesia was maintained with sevoflurane, and Group B, in which anesthesia was maintained with propofol. The MMSE score before and after operation, perioperative laboratory index, incidence of postoperative cognitive dysfunction (POCD) and incidence of adverse events between the two groups were compared.Results:The MMSE score was significantly higher in Group B than in Group A after anesthesia (p<0.05). Serum levels of the brain injury markers neuron-specific enolase, S100β and matrix metalloproteinase 9 were significantly lower in Group B than in Group A (p<0.05). POCD incidence at 12 hour and 24 hour after operation was significantly lower in Group B than in Group A (p<0.05). There were no significant differences in the incidence of low cardiac output and thoracotomy bleeding between two groups.Conclusion:Compared with sevoflurane, the use of propofol during cardiac surgery with CPB can efficiently improve postoperative cognitive function without increasing the risk of adverse reactions.

Aortic valve replacement with or without myocardial revascularization in octogenarians. Can minimally invasive extracorporeal circuits improve the outcome?

The positive impact of minimally invasive extracorporeal circuits (MiECC) on patient outcome is expected to be most evident in patients with limited physiologic reserves. Nevertheless, most studies have limited their use to low-risk patients undergoing myocardial revascularization. As such, there is little evidence to their benefit outside this patient population. We, therefore, set out to explore their potential benefit in octogenarians undergoing aortic valve replacement (AVR) with or without concomitant myocardial revascularization. Based on the type of the utilized ECC, we performed a retrospective propensity score-matched comparison among all octogenarians (n = 218) who received a primary AVR with or without concomitant coronary artery bypass grafting in our institution between 2003 and 2010. A MiECC was utilized in 32% of the patients. The propensity score matching yielded 52 matched pairs. The 30-day postoperative mortality (2% vs. 10%; p=0.2), the incidence of low cardiac output (0% vs. 6%; p=0.2) and the Intensive Care Unit (ICU) stay (2.5 ± 2.6 vs. 3.8 ± 4.7 days; p=0.06) were all in favour of the MiECC group, but failed to reach statistical significance while the 90-day postoperative mortality did (2% vs. 16%; p=0.02). MiECCs have a positive influence on the outcome of octogenarians undergoing AVR with or without concomitant coronary artery bypass grafting. Their use should, therefore, be extended beyond isolated coronary artery bypass graft (CABG) surgery.

Coronary Sinus Lactate as Marker of Myocardial Ischemia in Cardiac Surgery: Correlation with Morbidity and Mortality after Cardiac Surgery / Lactatul din sinusul coronarian - marker al ischemiei miocardice în chirurgia cardiacă: corelaţii cu morbiditatea şi mortalitatea postoperatorie

AbstractIntroduction. Perioperative myocardial injuries are one of the most frequent causes of morbidity and mortality after cardiac surgery, the most common etiology being the poor myocardial protection during aortic crossclamp. During aortic crossclamp progressive accumulation of lactate and intracellular acidosis are well-known phenomena, and are associated with alteration of myocardial contractile function. Our objective was to study the coronary sinus lactate levels as a predictor of postoperative hemodynamic outcome in open-heart surgical patients.Material and methods. We performed a prospective clinical trial, including 142 adult patients with elective cardiac surgery. Anterograde cardioplegia was administered in 82 patients, retrograde cardioplegia in 60 (in 30 patients it was administrated intermittently and in 30 continuously). Blood was collected simultaneously from the aortic cardioplegic line (inflow) and from coronary sinus or the aortic root (outflow) before aortic crossclamp, after crossclamp at every 10 minutes and after crossclamp removal at 0 and 10 minutes. All patients were operated on cardiopulmonary bypass with cardiac arrest, using warm-blood cardioplegia for cardioprotection.Results. Lactate levels showed increasing values during aortic crossclamp, and a rapid decline after crossclamp removal. The incidence of low cardiac output was significantly higher in patients with lactate levels that exceeded 4 mmol/L. In patients who died in the postoperative period, lactate level was even higher (5 mmol/L), with only a modest recovery after crossclamp removal.Conclusion. Monitoring lactate level in coronary sinus blood is a reliable method and has a good prognostic value regarding postoperative morbidity and mortality in open heart surgery

THE ABC TRIAL - DOES ALL-BLOOD CARDIOPLEGIA PREVENT BLOOD TRANSFUSION IN CARDIAC SURGERY? A SINGLE CENTER PILOT STUDY

s S227 was classified into a high RDW group and others were classified into a control group. Thrombolysis in Myocardial Infarction (TIMI) risk scores, angiographic characteristics, inhospital percutaneous or surgical revascularization, as well as 30-days major adverse cardiac event (MACE) including death, recurrent myocardial infarction, target vessel revascularization and lethal ventricular arrhythmias were compared between the two groups. RESULTS: Among 340 patients, 31 patients (9.1%) were classified into the high RDW group and 309 patients (90.9%) were classified into the control group. Mean RDW was 18.3 2.6% in the high RDW group and 13.8 0.9% in the control group. Patients with high RDW were more likely to have hypertension (93.5% vs. 73.1%, p1⁄40.01), chronic kidney disease (51.6% vs. 30.4%, p1⁄40.02) and anemia (11.3 1.6 g/dl vs. 13.2 1.7g/dl, p<0.001). Patients with high RDW had higher TIMI risk scores (4.2 1.2 vs. 3.6 1.5, p1⁄40.017) compared to the control group. Patients with high RDW had a higher rate of 30-days MACE (12.9% vs. 2.9%, p1⁄40.001) compared to the control group, and this association remained significant after adjusting for the baseline hemoglobin levels (odds ratio 2.878; 95% confidence interval 1.66 to 24.1; p1⁄40.004). There was no significant difference in peak troponin values, the rates of inhospital revascularization, pre-procedural impaired coronary flow, and the existence of coronary thrombus between the two groups. CONCLUSION: In patients with NSTEMI, high RDW defined as greater than 1SD was significantly associated with a higher TIMI risk score and a higher rate of 30-days MACE. After adjusting for the baseline hemoglobin levels, high RDW remained significantly associated with a higher rate of 30-days MACE. 337 THE ABC TRIAL DOES ALL-BLOOD CARDIOPLEGIA PREVENT BLOOD TRANSFUSION IN CARDIAC SURGERY? A SINGLE CENTER PILOT STUDY C Deshaies, RD Stanzel, KJ Buth, AB Fagan, GM Hirsch, SB O’Blenes Halifax, Nova Scotia BACKGROUND: All-blood cardioplegia (ABC) has emerged as an alternative to standard 4:1 diluted blood cardioplegia (DBC) due to its theoretical advantages of limiting hemodilution, blood transfusion, and myocardial edema. METHODS: We performed a randomized, double blind pilot study to determine feasibility and sample size for a multicenter trial comparing both strategies. Patients were eligible if undergoing CABG, aortic, mitral or combined surgery. Exclusion criteria included pre-op mechanical support, endocarditis, previous cardiac surgery, and recent irreversible anticoagulation. Retrograde autologous priming was used in all cases. Strict transfusion criteria were followed during hospital admission. RESULTS: Of 650 cases performed at our centre between February and September 2013, 246 patients were screened and 36 of them (15%) were eligible, consented, and randomized (ABC n1⁄418; DBC n1⁄418). Comorbidities, procedure types, and cross-clamp time, were similar in each group (table 1). There was no mortality. The total volume of cardioplegia delivered in each group was similar but the amount of crystalloid in the cardioplegia was significantly less in the ABC group (73 vs. 516 mL; p < .0001) (figure 1). Nonetheless, crystalloid in the cardioplegia represented only 1% (ABC) vs. 8% (DBC; p < .0001) of the total intraoperative crystalloid administration, and 0.7% (ABC) vs. 5% (DBC; p < .0001) of the fluid received in the first 24 hours of care. Four ABC and 2 DBC patients were transfused a total of 6.75 and 5 pRBC units. There was 100% adherence to our transfusion protocol. One subject in the ABC group, who was initially transfused during his admission, also received an additional unit in a peripheral center after discharge. The drop in hemoglobin from pre-op to lowest value (g/L: 51 vs. 49; p 1⁄4 0.60), the incidence of low cardiac output (%: 16 vs. 22; p 1⁄4 0.99) and markers of myocardial injury (16-hr Tn-T: 227 vs. 327; p 1⁄4 0.08) were similar in each group. Based on the DBC transfusion rate of 11% and a power of 80%, 898 to 2892 patients per arm would be required to show a relative risk reduction between 20 and 35%. CONCLUSION: The study demonstrated the feasibility of our design. However, over 1000 subjects per group will be required to detect a clinically significant reduction in transfusion. Modification of inclusion criteria, targeting patients at high risk of transfusion, would likely reduce the necessary sample size but would negatively impact recruitment rate and generalizability of the results. S228 Canadian Journal of Cardiology Volume 3

The Enemy of Good …

The Enemy of Good …

Changing trends in emergency coronary bypass surgery

Patients undergoing emergency coronary artery bypass grafting represent a unique and high-risk population that remains challenging for cardiac surgeons. We examined the changing trends in patients undergoing emergency bypass grafting over the past 20 years. We conducted a retrospective review of our database between 1990 and 2009 and patients were divided into 2 groups based on year of operation: 1990-1999, n = 393; 2000-2009, n = 184. The primary outcomes of interest for this study are operative mortality and incidence of low cardiac output syndrome. The percentage of patients undergoing emergency coronary bypass grafting has decreased from 2.7% to 1.7% over time. The percentage of patients with dyslipidemia, hypertension, triple vessel disease, peripheral vascular disease, and left main disease increased over time (P < .05). Operative mortality remained at 8.1% in both year groups. Preoperative hypertension, congestive heart failure, left ventricular ejection fraction less than 20%, and previous cardiac surgery independently predicted operative mortality by logistic regression analysis. Low cardiac output syndrome developed in 25% of the patient population undergoing emergency bypass grafting. The independent predictors of low cardiac output syndrome were small body surface area, congestive heart failure, shock, myocardial infarction, earlier decade (1990-1999) and increased age. Despite a changing preoperative risk profile, the operative mortality of emergency coronary artery bypass grafting has remained stable over the years. However, mortality remains significantly above the observed mortality in elective bypass grafting. Continued improvements in the management of heart failure and the care of the elderly will likely result in reduced risks of emergency coronary artery bypass grafting.

Acute Pancreatitis after Cardiac Transplantation and Other Cardiac Procedures: Case-Control Analysis in 24,631 Patients

Previous series have identified an increased risk of developing acute postoperative pancreatitis in heart transplant recipients and other cardiac surgical patients, and some suggest that mortality is significantly increased when pancreatitis occurs in the transplant setting. We conducted a retrospective case-control analysis of adult patients undergoing orthotopic heart transplant or other cardiac procedures from April 1985 through June 1996 at our medical center. Specific risk factors for outcome were assessed including low cardiac output, intra-aortic balloon pump usage, exogenous calcium repletion, immunosuppression, cytomegalovirus infection, cholelithiasis, prior pancreatitis, and Acute Physiology and Chronic Health Evaluation (APACHE) II scores. There was a 30-fold increase in the incidence of pancreatitis in the heart transplant group [12 of 394 (3%) vs 27 of 24,237 (0.1%); P < 0.01]. Compared with the nontransplant cardiopulmonary bypass patients, the transplant patients experienced a statistically significant increased incidence of immunosuppression and three or more risk factors. Transplant patients with pancreatitis demonstrated a significant increase in APACHE II scores and the incidence of three or more risk factors compared with their transplant control group. Patients undergoing nontransplant cardiac procedures and developing pancreatitis had significantly increased cross-clamp times, incidence of low cardiac output, APACHE II scores, and incidence of three or more risk factors compared with their nontransplant cohort. In conclusion, there is a significant increase in the incidence of pancreatitis after orthotopic heart transplant compared with other cardiac procedures. Analysis demonstrates the additive effect of multiple individual risk factors. Immunosuppression confers significant additional risk for pancreatitis in the orthotopic heart transplant patient.

Antegrade crystalloid cardioplegia vs antegrade/retrograde cold and tepid blood cardioplegia in CABG

Background. This study evaluated the myocardial protective strategies in isolated coronary bypass surgeries. Methods. One hundred and twenty-eight patients were prospectively randomized to 3 techniques of myocardial protection; group I (n = 47) antegrade/retrograde tepid blood cardioplegia, group II (n = 40) antegrade/retrograde cold blood cardioplegia with topical cooling, group III (n = 41) antegrade crystalloid cardioplegia with topical cooling. Results. The incidence of spontaneous defibrillation was significantly higher in group I ( p <0.001) while the incidence of low cardiac output was not different between the 3 groups. The incidence of ventricular arrhythmia was higher in group III ( p <0.016 group III vs I). There was no significant statistical difference in hemodynamic recovery between the 3 groups. CK-MB levels were significantly lower in group I versus the other 2 groups, ( p= 0.0013, 0.04). Acid release and oxygen extraction were higher in group II than in group I ( p= 0.06) during cardioplegia and reperfusion. Lactate release was less in group I at the release of aortic cross-clamp, and reperfusion. There was no significant difference between the 3 groups in ICU stay, ventilation time, or hospital complications. Conclusions. Tepid blood cardioplegia showed superiority in metabolic and functional recovery, whereas crystalloid cardioplegia had the highest incidence of postoperative arrhythmias. There was no significant statistical difference between the 3 groups in hospital mortality and morbidity.

Intropic and vasodilator therapy and fluid refractory pediatric septic shock 185

Introduction: Fluid refractory septic shock in adults occurs for the most part as a result of vascular failure. The use of inotropes and vasodilators is infrequent in this setting. Developmental differences in cardiac function could contribute to a different cardiovascular response in pediatric septic shock. We hypothesized that children with fluid refractory septic shock frequently have a high incidence of low cardiac output and high vascular resistance which responds to inotrope and vasodilator therapy.

Effectiveness of coenzyme Q10 on myocardial preservation during hypothermic cardioplegic arrest

A prospective, randomized, double-blind trial assigned 11 patients to receive coenzyme Q10 and 11 to receive none. Patients pretreated with coenzyme Q10 had a lower left atrial pressure and a lesser incidence of low cardiac output. They also had a wider pulse pressure. The right and left ventricular myocardial ultrastructure was better preserved in patients receiving preoperative treatment with coenzyme Q10. There was no demonstrable benefit to the atrial myocardium. (J THORAC CARDIOVASC SURG 1994;107:242-7)

Clinical Evaluation of Hypothermic Ventricular Fibrillation, Multi-Dose Blood Cardioplegia, and Single-Dose Bretschneider Cardioplegia in Coronary Surgery

37 patients undergoing coronary revascularization were randomly assigned to three protocols for intraoperative myocardial protection: hypothermic ventricular fibrillation (HF) (n = 13), multi-dose blood cardioplegia (BCP) (n = 12) and single-dose Bretschneider's crystalloid cardioplegia (CCP) (n = 12). As intraoperative markers of ischemic damage myocardial ultrastructure, ATP, and CP contents were determined in left ventricular biopsy specimens taken before and after cardiac arrest. Release of serum enzymes (CK, CK-MB, LDH, SGOT) was determined pre- and postoperatively. Hemodynamic data were assessed before, during, and after operation. The incidence of low cardiac output, positive inotropic support, intraaortic balloon counterpulsation, peri-operative myocardial infarction, rhythm disturbances, and the rate of spontaneous defibrillation was compared between groups. The results show a better preservation of high energy phosphates in the BCP group as compared to the HF and CCP groups. Myocardial ultrastructure showed moderate ischemic damage in the hypothermic fibrillation group; in contrast, only slightly deteriorated cells were seen after cardiac arrest, when cardioplegia was used. The incidence of rhythm disturbances was 25% for HF and 42% for CCP. In contrast, only 17% of new rhythm disturbances were seen in the BCP group. Functional recovery (i.e. CI and SWI) of hearts protected with BCP was generally greater as compared to HF and CCP. Release of MB-creatine-kinase isoenzyme was higher in the HF group as compared to cardioplegia. Clinical outcome in terms of incidence of peri-operative infarction, positive inotropic support and low cardiac output was superior in the BCP group but not significantly different between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Nifedipine as an adjunct to St. Thomas’ Hospital cardioplegia: A double-blind, placebo-controlled, randomized clinical trial

The cardioprotective effect of the addition of the slow calcium-channel blocker nifedipine to cardioplegic solution was tested in two double-blind placebo controlled randomized studies. The first study included 24 patients undergoing aortic-coronary bypass grafting, and the second included 24 patients undergoing aortic valve replacement. Nifedipine at a dose of 200 micrograms/L or placebo was added to St. Thomas' Hospital cardioplegic solution. The following markers of ischemia were used: adenosine triphosphate and its catabolites, creatine phosphate and inorganic phosphate, determined in transmural left ventricular biopsy specimens taken before, at the end of, and after aortic cross-clamping; hemodynamic recovery 15 minutes after cessation of cardiopulmonary bypass; clinical outcome in terms of the incidence of arrhythmias, low cardiac output, positive inotropic support immediately after operation, and follow-up at 15 months. The main difference between the two studies was that myocardial temperature during cross-clamping remained constant at 14 degrees C in coronary bypass grafting but increased to 25 degrees C in valve operations despite the application of the same amounts of cardioplegic solutions. This lower temperature resulted in better preservation of high-energy phosphates in coronary bypass operations as compared to the placebo group having valve replacement operations. According to analysis of variance, a drug effect could be demonstrated only in the aortic valve replacement study: Accumulation of breakdown products of the adenine nucleotide pool was less in the nifedipine group than in the placebo group (p less than 0.05). Adenosine triphosphate decreased only to 84% in the nifedipine group and to 72% in the placebo group. Despite this adenosine triphosphate-sparing effect, weaning from cardiopulmonary bypass was more difficult in the nifedipine group. Left ventricular stroke work index 15 minutes after bypass was decreased to 72% of the prebypass value in the nifedipine group (t test, p less than 0.01) and only to 86% in the placebo group (p = NS). In contrast, after the patients were admitted to the intensive care unit, the incidence of low cardiac output tended to be lower in the nifedipine group than in the placebo group: 33% versus 58% (p = NS). In conclusion, ischemia-induced degradation of nucleotides as it occurs when myocardial cooling is inadequate can be prevented by the addition of nifedipine to the St. Thomas' Hospital cardioplegic solution. This effect, however, is not associated with an improved clinical outcome.

A new method for the quantitative standardization of cross-sectional areas of the pulmonary arteries in congenital heart diseases with decreased pulmonary blood flow

A new angiographic method for quantitative standardization of cross-sectional area of bilateral pulmonary arteries, the PA-index, and retrospective analysis of the PA-index in different types of operative procedures are presented. This study included 40 subjects in the normal control group, 46 patients in the tetralogy group, 26 patients in the Rastelli group, and 15 patients in the Fontan group. The normal value of the PA-index was 330 +/- 30 mm2/BSA and was consistent in a wide range of body surface areas from infancy to adolescence. The PA-index in the tetralogy and Rastelli groups ranged from 100 to 400 mm2/BSA. There were no early deaths in the tetralogy group, but the incidence of low cardiac output was higher in patients with a smaller PA-index, especially when the PA-index was less than 150 mm2/BSA. Low cardiac output was more severe in the Rastelli group. The operative mortality was significantly affected by the PA-index. In the Rastelli group, all of the patients with a PA-index of less than 200 mm2/BSA died, whereas the mortality rate in patients with a PA-index of more than 200 was only 6% (p less than 0.01). The mortality rate was not influenced by any other factors, such as aortic cross-clamp time or age at operation. In the Fontan group, two patients with a PA-index of less than 250 mm2/BSA died of severe heart failure, and 12 of 13 patients with a PA-index of more than 250 survived (p less than 0.01). Our results indicated the validity of the PA-index in predicting the postoperative prognosis of the various entities. In tetralogy, all patients with a PA-index over 100 mm2/BSA can undergo correction safely; in Rastelli operation, those with a PA-index under 200 should have a palliative procedure first, whereas those with a PA-index over 250 can be considered good candidates for the Fontan procedure. The PA-index may also serve a useful guide in comparing surgical results from different institutions with patients having anomalies of varying severity.

Intermittent aortic cross-clamping versus St. Thomas’ Hospital cardioplegia in extensive aorta-coronary bypass grafting: A randomized clinical study

Myocardial preservation was assessed in 72 patients undergoing extensive myocardial revascularization. The patients were allocated at random to three surgical techniques: Group 1, intermittent aortic cross-clamping at 32 degrees C; Group 2, intermittent aortic cross-clamping at 25 degrees C; and Group 3, St. Thomas' Hospital cardioplegia. As intraoperative markers of ischemic damage, adenosine triphosphate, creatine phosphate, and glycogen contents were determined in transmural left ventricular biopsy specimens taken at the beginning and at the end of cardiopulmonary bypass. Ultrastructure was studied in a similar pair of biopsy specimens. Release of myocardium-specific creatine kinase isoenzyme was determined intraoperatively and postoperatively. Functional recovery was assessed before and after weaning from cardiopulmonary bypass. The incidence of low cardiac output, myocardial infarction, and rhythm disturbances was compared between groups. Finally, actuarial survival and event-free curves were studied after 18 months' follow-up. The results show a better preservation of high-energy phosphates, glycogen, and ultrastructure in the cardioplegia group as compared to the two cross-clamp groups. However, severe myocardial damage was never observed. Release of MB creatine kinase isoenzyme was the same in all three groups. Functional recovery of the hearts immediately after cessation of cardiopulmonary bypass was better in the cardioplegia group, but the incidence of rhythm disturbances (atrioventricular conduction problems) was higher in the cardioplegia group than in the other two groups (p less than 0.05). Clinical outcome in terms of incidence of perioperative infarction, survival, and event-free follow-up was not different between groups. It is concluded that both techniques (aortic cross-clamping at 32 degrees C or 25 degrees C and St. Thomas' Hospital cardioplegia) offer good myocardial protection in extensive aorta-coronary bypass operations. St. Thomas' cardioplegia, however, in contrast to intermittent aortic cross-clamping, prevents the onset of ischemia-induced deterioration of cardiac metabolism, i.e., destruction of the adenine nucleotide pool.