Routine preop testing before vitreoretinal surgery

Take home

Not all patients may benefit from routine testing prior to surgery. Selective screening may be best for those at greatest risk for adverse systemic events.

By Roxanne Nelson; Reviewed by Ajay Shalwala, MD

Philadelphia-Preoperative medical testing prior to vitreoretinal surgery may help to reduce the risk of adverse events in some patients.

However, routine testing may not benefit all patients, and a better option may be selective screening for those who are at the greatest risk for adverse systemic events.

"We believe that our results demonstrate that routine preoperative testing does not measurably improve the safety of vitreoretinal surgery and that reduction of such testing may considerably reduce health-care costs," said study author Ajay Shalwala, MD, Wills Eye Institute, Philadelphia.

Dr. Shalwala-pointing out that the research itself was conducted at Vanderbilt Eye Institute, Nashville, TN-also noted that individuals with certain comorbidities were at a greater risk of complications.

“Our results also suggest that patients with coronary artery disease, asthma, and chronic renal disease and those undergoing general anesthesia are at greater risk of postoperative systemic complications,” he said. “Therefore presence of these risk factors should alert physicians to the need for greater preoperative and postoperative monitoring.

“Conversely, the absence of these risk factors may allow physicians to reduce the burden and cost of preoperative testing,” Dr. Shalwala added.

As with other types of procedures, screening medical tests are routinely performed on patients in preparation for vitreoretinal surgery.

However, the benefit of routine testing is uncertain.

Routine preoperative medical testing prior to elective surgery has been questioned. Some data suggest that there are no significant differences in the rates of either intraoperative and postoperative events between patients who did or did not undergo the standard battery of preoperative testing.

In addition, preoperative testing is expensive, and adds to the overall economic health-care burden.

Predictive value

In this study, Dr. Shalwala and colleagues assessed the predictive value of routine medical testing for postoperative systemic adverse events among patients who were undergoing vitreoretinal surgery.

In a retrospective single center study, the researchers evaluated the medical charts of 2296 patients who were 17 years of age and older, who underwent vitreoretinal surgery between January 2002 and November 2011 at Vanderbilt University.

The charts for 2215 patients were reviewed for information on baseline comorbidities, preoperative testing, and postoperative adverse events that occurred within 30 days of their surgery.

Charts with less than 7 days of documented follow up were excluded from the study, and logistic regression analysis was performed to correlate adverse events with preoperative testing and comorbidities that were present at baseline.

Within this cohort, 89 patients experienced adverse events, and 12 patients had multiple events, for a total of 102 events. Within this subgroup, 73 (72%) of the adverse events occurred within the first 24 hours after surgery, while the remaining 29 (28%) occurred between postoperative days 1 and 30.

Overall, the incidence of adverse events following vitreoretinal surgery in this series was 4%.

The most common adverse events observed were bradycardia (26 events) and desaturation (22 events). More serious events that were identified included 2 cases of myocardial infarction, 1 case of acute heart failure, and 3 patients with respiratory failure who subsequently required mechanical ventilation, according to Dr. Shalwala.

“There were no deaths observed in our study cohort,” he said. “The majorities of adverse systemic events, however, were mild, transient, and did not result in permanent morbidity.”

Co-existing medical illnesses appeared to influence the occurrence of adverse events. The study results showed that coronary artery disease, chronic renal failure, and asthma all were independent predictors of post surgical events (p < 0.05).

However, age, race, and smoking history, and the presence of diabetes, COPD, smoking history, history of cerebrovascular accident, chronic liver disease, and systemic malignancy were not associated with events.

The use of general anesthesia also increased the risk, as compared with use of a local anesthetic (p < 0.001). Multivariate logistic regression analysis demonstrated no significant correlation between preoperative testing and postoperative adverse events, and by the end of the study, no test was found useful to change the rate of adverse events

The authors conclude that general anesthesia and the presence of specific comorbidities increased the risk of adverse events.

The data in this study may therefore assist in selective preoperative testing for patients who are at the greatest risk of adverse events, and lower the burden of routine testing for those who are at low risk.

Ajay Shalwala, MD

E: ashalwal@gmail.com

The authors declare no financial relationships. Grant support for the study was given by Research to Prevent Blindness to Vanderbilt Eye Institute.

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