[Wall stress in the assessment of left ventricular function in surgery of abdominal aortic aneurysm. Validity and importance of transesophageal echocardiography (TEE) in intraoperative monitoring].

OBJECTIVE

To verify the applicability and the clinical significance of left ventricular wall stress determinations by intraoperative transesophageal echocardiography (TEE) during resections of abdominal aortic aneurysms.

DESIGNS

Prospective comparison of changes in left ventricular wall stress between two groups of patients with and without coronary artery disease.

SETTING

Operatory room of Universitary Institute.

PATIENTS

Twenty-three patients with abdominal aortic aneurysms; 8 had clinically evident coronary artery disease (CAD+); 15 patients did not have clinical or electrocardiographic evidence of coronary artery disease (CAD-).

INTERVENTIONS

Resection of the aortic aneurysm and insertion of a synthetic prosthesis.

MEASUREMENTS AND MAIN RESULTS

During operation transesophageal monitoring of left ventricular volumes and wall stress was performed during induction of anesthesia (T1), for two minutes after aortic clamping (T2), at the end of the proximal anastomosis (T3), for two minutes after aortic declamping (T4) and at the end of the procedure (T5). Circumpherential stress at end systole (sES) and end diastole (sED) was more sensitive than hemodynamic and volumetric parameters in detecting changes i function of the ischemic myocardium. In detail we observed: a significant increase of sES in CAD+versus CAD- at T2: 98 (sd 18) vs 83 (sd 14) 10(3) dyne/cm2. a significant increase of sED in CAD + versus CAD- at T2: 28.5 (sd 6) vs 22 (sd 4.5) 10(3) dyne/cm3. a similar trend of sES and sED at T4: 73 (sd 20.5) vs 46 (sd 15) 10(3) dyne/cm2 and 31 (sd 12) vs 16 (sd 7.7) 10(3) dyne/cm2 respectively. a significant increase of sED in CAD + at T5 (about 20' after T4): 26.5 (sd 9.5) vs 16 (sd 5.2) 10(3) dyne/cm2 which is expression of a persistent reduction of ventricular compliance in the ischemic patients.

CONCLUSIONS

Wall stress modifies MVO2 and subsequently is sensitive in detecting changes in myocardial performance. TEE could valuably integrate routine hemodynamic monitoring of patients with coronary heart disease who undergo surgical resection of abdominal aortic aneurysms.