The transfer function between aortic pressure and radial artery pressure can be approximated with second-order response system. Pressure wave deformation between aortic pressure waveforms (APW) and radial pressure waveforms (RPW) was quantitatively analyzed with a 4-element model consisting of aortic characteristic impedance (Zc), inertance (L), peripheral resistance (Rp), and compliance (C), which shows the nature of second-order response, to clarify the physiological background of cardiovascular conditions accounting for pressure wave distortion. Therefore, we have provided a theoretical framework to simulate the change in shapes of arterial blood pressure waves using the four parameter (Zc, L, Rp, C), corresponding to the systemic circulation. The results suggest that large aortic impedance, low peripheral resistance, and increased compliance cause the damping of RPW. The model approach enables us to recognize the physiological causality of pressure wave deformation in relation to the cardiovascular conditions.
Three-dimensional (3D) imaging provides a more comprehensive view of annular structure and allows accurate reconstructions of mitral valve anatomy to evaluate the feasibility of intraoperative 3D TEE in patients with mitral valve prolapse (MVP). A 37-year-old man was scheduled to undergo mitral valve plasty due to mitral regurgitation. Pre-operative transthoracic echocardiography showed moderate mitral valve regurgitation with a portion of a posterior leaflet(P2). 2D TEE examination was performed after tracheal intubation, by which 3D TEE mitral valve formation was constructed using 4D surgical view software (Tomtec TM). The location of the prolapse of the mitral valve was assessed with six valve elements (A1, A2, A3, P1, P2, P3: 6 points) and the data were examined. 2D TEE findings of MVP localization were in P1, P2. 3D TEE findings were A3, P2 prolapse at blood pressure 80/52 mmHg. And A3, P2, P3 prolapse at blood pressure 100/72 mmHg. Intraoperative 3D TEE evaluation of MVP was possible before initiation of the surgical procedure and feasible. Accurate anatomical finding of MVP is sometimes difficult to understand with use of 2D TEE findings and even with surgical finding after cardiac arrest. 3D data should be of value to the surgeon when performing mitral valve repair.
A 75-year-old man with unstable angina pectoris underwent coronary artery bypass grafting. Femoral IABP insertion was accomplished preoperatively, because of low left ventricular function. On the seventh postoperative day the IABP balloon rupture was detected. An attempt was made to remove the balloon at the bedside, but balloon entrapment was occurred. Surgical treatment was required for removing the balloon. In order to reduce operative invasion, the abdominal aorta and iliac artery were exposed through a small flank incision with retroperitoneum approach. The device was easily removed through a common iliac artery incision. Balloon rupture is a comparatively rare complication, but if occurs, the blood clot formation inside the balloon will result in balloon entrapment in the vessel frequently. Generally the case who needs the IABP as a mechanical assistance has a critical heart failure. Further the invasive laparotomy or large flank incision may worsen the hemodynamics status. Accordingly the minimal invasive technique was very important to reduce a patient’s burden.