Factors associated with occurrence of the intraleft atrial nonsmoke spontaneous individual contrast phenomenon after a Valsalva maneuver during transesophageal echocardiography.

Nonsmoke spontaneous individual contrast (NSSIC) is a phenomenon that is a contrast effect appearing from the right pulmonary vein to the left atrium just after a Valsalva maneuver in a transesophageal echocardiography study without administration of any contrast medium. The goal of this study was to characterize factors associated with occurrence of NSSIC. Transesophageal echocardiography was performed in 228 consecutive patients to determine the presence or absence of the patent foramen ovale and valvular disease and various patient characteristics and laboratory data. NSSIC was demonstrated in 109 (47.8%) of 228 patients. Factors associated with occurrence of NSSIC included younger age, male gender, smoking habit, taller height, heavier weight, higher hematocrit, higher plasma level of fibrinogen, lower D-dimer levels and presence of mitral valve strand. Multiple logistic regression analysis indicated that higher hematocrit and plasma levels of fibrinogen were most closely associated with the presence of NSSIC. Thus, NSSIC may occur secondary to specific blood rheologic factors during the Valsalva maneuver.