The standard of care in cardiac surgery, intraoperative transesophageal echocardiography (TEE), is safe, according to researchers. A recent review found an overall complication rate of 1.4% related to the imaging and diagnostic technique. It also pinpointed several significant risk factors for complications.
“The use of transesophageal echocardiography is ubiquitous in cardiac surgical practice,” said Razvan Purza, MD, who conducted the research as a medical student at the University of Manitoba, in Winnipeg. “There are various studies that demonstrate its safety, but they are few and far between, and very few recent cohort studies. With that in mind, the purpose of this retrospective cohort study was to determine the incidence of TEE complications, as well as the risk factors in a contemporary cardiac surgical population.”
A Hunt for TEE-Related Complications
To that end, Dr. Purza and his colleagues analyzed the records of 7,954 cardiac surgical cases performed at the institution between April 1, 2004, and April 30, 2012. Patients who may have suffered a TEE-related complication were identified using International Classification of Diseases, 10th Revision (ICD-10) codes related to:
- vocal cord and laryngeal injury;
- accidental puncture/laceration during a procedure; and
- hemorrhage/hematoma complicating a procedure.
Moreover, any case requiring postoperative bronchoscopy or consultation with otolaryngology, the gastrointestinal bleeding team, general surgery or thoracic surgery due to a potential TEE-related complication was flagged for a manual chart review.
Cases with potential TEE-related complications were then compared with all cases in the institution’s cardiac surgical database for which no complication potentially related to TEE was reported. Univariate and multivariate models were developed to identify risk factors for TEE complications.
As Dr. Purza reported at the 2016 annual meeting of the Canadian Anesthesiologists’ Society (abstract 150081), 1,074 charts had ICD-10 codes that triggered a manual review for potential TEE complications. A total of 111 cases (1.4%) were subsequently identified with possible TEE-related complications. “We found that although 61% of complications were identified within the first week,” Dr. Purza said, “they continued to be identified on the eighth postoperative day and beyond” (Figure 1).
Figure 1. Complications Reported During Week 1
NOS, not otherwise specified
The most common complications (Figure 2) were esophageal and/or gastric complications (n=73) and persistent dysphagia requiring intervention (n=24). “The literature varies widely on dysphagia rates,” he said. “Some suggest dysphagia as high as 50%, although they tend to be mild and resolve on their own. Our study methods allowed us to identify cases of persistent dysphagia requiring intervention.” No esophageal perforations were observed during the study period.
Figure 2. Types of Complications Found in First 30 Days
The study’s multivariate analysis revealed an increased risk for complications associated with age (odds ratio [OR], 1.04 per year), body mass index (BMI; OR, 0.95 per unit), previous cerebrovascular accident or transient ischemic attack (TIA; OR, 3.59), procedure other than isolated coronary artery bypass grafting (CABG) surgery (OR, 1.73), return to the operating room (OR, 6.07) and cardiopulmonary bypass (CPB) time (OR, 1.01 per minute).
“Low BMI increased risk potentially due to probe-size mismatch,” he said. “We thought previous CVA [cerebrovascular accident] or TIA was a significant risk factor because of either overall frailty or the risk of multiple surgical complications. Procedures other than isolated CABG may also pose increased risk due to operative duration, increased probe manipulation requiring multiple imaging as well as increased CPB time.”
The authors noted that while the study’s 1.4% overall complication rate is greater than in previous studies, their identification strategy may have played a role. “We believe it may be because we were able to identify patients in several ways,” Dr. Purza explained. “We also looked at the entire perioperative period, whereas previous studies had only looked at the intraoperative period or the very immediate postoperative period.”
“Some of the presentations of the problem go out as far as 30 days,” commented session moderator Blaine Kent, MD, associate professor of anesthesia pain management and perioperative medicine at Dalhousie University, in Halifax, Nova Scotia. “How are we confident that these complications are attributable to the TEE itself instead of something else?”
“We meant to be overly inclusive with our data in order to get as wide a range of possible complications as we could,” Dr. Purza replied.
Richard Hall, MD, professor of anesthesia, pain management and perioperative medicine; critical care; and pharmacology at Dalhousie University, expressed curiosity about some of the study’s associations, particularly dysphagia. “Presumably a percentage of these patients had a stroke of some sort, and some of those would have dysphagias,” Dr. Hall said. “So is it the stroke or the TEE?”
“That was actually one of the exclusion criteria,” Dr. Purza said. “We excluded patients if they had a postoperative CVA followed by documented dysphagia, because we thought that the CVA would be the cause of their dysphagia.”