S. Amodeo1, A. Pinna1,2,3, A. Masi1,2, I. Hatzaras1, E. Newman1,2, S. M. Cohen1, R. S. Berman1, G. H. Ballantyne1,2, H. L. Pachter1, M. Melis1,2 1New York University School Of Medicine,Department Of Surgery,New York, NY, USA 2New York Harbor Healthcare System VAMC,Department Of Surgery,New York, NY, USA 3University Of Sassari,Department Of General Surgery,Sassari, , Italy
Introduction: The lowest heart rate recorded during surgery is one of the 3 parameters required to calculate the Surgical Apgar Score (SAS), a 10-point prognostication score used to predict postoperative outcomes. We aimed to verify whether SAS maintains its validity in patients undergoing long-term treatment with beta blockers.
Methods: We queried our institutional clinical database for patients undergoing general surgery procedures between October 2006 and September 2011. Patients on long-term beta blockers were identified and defined the study population. We divided our study population into 4 groups according to their SAS: ≤4, 5-6, 7-8, 9-10. Study end-points were overall morbidity and 30-day mortality. Differences between SAS groups were evaluated with Pearson’s chi-square or ANOVA, as appropriate.
Results: Of the 2125 patients who underwent general surgery over the study period, 568 (26.7%) were taking beta blockers at the time of their operation and represented our study population. They were distributed as follows: SAS ≤ 4: n= 10 (1.8%), SAS 5-6: n= 78 (13.7%), SAS 7-8: n= 181 (31.9%), SAS 9-10: n= 299 (52.6%). There were no differences in age, sex, race, history of smoking or alcohol abuse across SAS groups. Furthermore, no differences were seen in the incidence of diabetes, previous history of transient ischemic attacks, cerebrovascular accidents or peripheral vascular disease. A low SAS was associated with worse functional status (p<0.001), and increased incidence of certain preoperative conditions (congestive heart failure, dyspnea, acute renal failure, ascites: p<0.001; severe COPD: p=0.001; history of esophageal varices: p=0.002; hypertension, history of angina: p<0.05). Accordingly, a low SAS correlated with a higher American Society of Anesthesiologists score (p<0.001). The vast majority of patients with low SAS underwent major or extensive procedures (100% and 85.9% for score ≤ 4 and 5-6, respectively), while high SAS patients mostly underwent minor or intermediate surgery (77.3% for score 9-10). Post-operative morbidity was 60% for score ≤ 4, 46.2% for score 5-6, 27.6% for score 7-8, and 10.4% for score 9-10 (p<0.001). The mean number of complications for each group, respectively, was 1.40 ± 1.7, 1.00 ± 1.4, 0.56 ± 1.2, and 0.15 ± 0.5. Thirty-day mortality rate was 10% for score ≤ 4, 12.8% for score 5-6, 3.3% for score 7-8, and 0.7% for score 9-10 (p<0.001).
Conclusion: Correlation of SAS and risk of surgical complication is maintained in a population of general surgery patients treated with beta blockers. Correlation of SAS with pre-operative conditions and performance status was also confirmed in this patient group.