Does the Nuss procedure for treating pectus excavatum compromise the long term internal mammary artery flow? A systematic review

INTRODUCTION The Nuss procedure is the most common procedure used to treat patients with pectus excavatum. The effect of the Nuss bars on the long-term internal mammary artery flow (IMA) is not well studied. This could have an impact on patients requiring a coronary artery bypass grafting surgery after the Nuss procedure. We performed a systematic review to study the impact of the Nuss bars on the IMA long term flow. METHODS A Medline search from January 1990 to August 2020 was performed using [Nuss OR thoracoscopic pectus OR minimally invasive pectus] AND [Internal mammary OR Internal thoracic OR IMA OR ITA]. English language papers only were included. This trial was registered with PROSPERO under registration number CRD42021234010. RESULTS A total of 48 papers were identified using the reported search, of which three represented the best evidence to answer the clinical question. One study looked at the IMA flow via computed tomography (CT)-angiography on the 10th postoperative day after the Nuss procedure and found 15 out of 34 patients (44%) to have abnormal IMA blood flow but with no clinical consequences. Two studies looked at the IMA flow after removal of the Nuss-bar. The first study utilized CT-angiography on the 5th postoperative day after Nuss-bar removal and found four out of the six patients studied (67%) to have abnormal flow. The last study was composed of 19 patients and looked at IMA flow during the presence of the Nuss-bars and after its removal utilizing Doppler-angiography. It found 11 out of 19 patients (58%) to have abnormal blood flow with the bars in place. After removal of the bars, only two patients (10%) were found to have unilateral IMA obstructed flow. CONCLUSION In patients undergoing the Nuss procedure for management of pectus excavatum, the internal mammary artery flow is compromised in 44%-58% of patients with the bar in situ. When these patients are assessed 10 days following removal of the bar, some reversal of compromised IMA flow is evident. However, in up to 67% of patients, abnormal IMA flow remains. Further studies are required to determine whether this abnormal flow is permanent, which will require examining patients at longer follow-up intervals. Patients undergoing coronary artery bypass grafting who have a history of a Nuss procedure should receive preoperative IMA imaging.