M. R. Helder1, H. V. Schaff1, A. Pochettino1, H. Connolly1 1Mayo Clinic,Cardiovascular Surgery And Cardiovascular Diseases,Rochester, MN, USA
Introduction: Practice guidelines recommend repair for aortic root aneurysms in adult patients with Marfan syndrome based on absolute diameter despite the recognized variation based on age, sex, and body surface area. Echocardiographic Z-scores have been used in multiple pediatric patient studies outlining a “normal z-score” range. However, the aortic Z-score at which adult patients should be offered an operation has not been defined.
Methods: After IRB approval, we retrospectively examined the preoperative echocardiography data of all patients with Marfan syndrome who underwent elective aortic root repair from February 11, 2005 to September 3, 2010 based on either aortic root diameter threshold or increase in aneurysm diameter over time. Aortic root diameters were measured at sinus level in all but two patients where the mid-ascending aorta was the largest diameter. Age, sex, and body surface area were gathered from the electronic medical record and used to calculate a Z-score based using the following equation: Z = (measure diameter – predicted diameter)/0.261 cm. Predicted diameter (cm) = 2.423 + (age X 0.009) + (BSA X 0.461) − (sex X 0.267), where male sex = 1, female sex = 2.
Results: Fifty-eight adult patients, average age of 36±13 years (71% male), underwent aortic root repair. Median aortic root diameter was 52 mm, range of 32 – 71 mm. Average aortic root diameter was 54±5 mm. This corresponded to a median aortic Z-score of 6 (range, -1.6 to 14). Average aortic Z-scores were 6±3. Mean ejection fraction, preoperatively, was 58±7%. Eleven patients had an aortic root diameter < 45 mm; 4 of these patients (36%) had corresponding Z-scores greater than 4.
Conclusion: This study describes aortic of Z-scores of patients that underwent aortic root repair based on indications dictated by current practice guidelines. Z-scores of some patients indicated a larger relative aneurysm than would have been clear by aneurysm diameter alone. Aortic Z-scores should be studied further and incorporated into the clinical decision making of whether or not to offer a patient aortic repair. Based on this descriptive data, a z-score > 3 could be used as an operative indication for aortic repair in patients with Marfan syndrome.