Search

Wave intensity (WI) is a new hemodynamic index, which is defined as (dP/dt)(dU/dt) at any site of the circulation, where dP/dt and dU/dt are the time derivatives of blood pressure and velocity, respectively. Arterial WI in normal subjects has two positive sharp peaks. The first peak occurs during early systole when a forward-traveling compression wave is generated by the left ventricle. The magnitude of this peak increases markedly with an increase in cardiac contractility. The second peak, which occurs towards the end of systole, is caused by generation of a forward-traveling expansion wave by the ability of the left ventricle to actively stop aortic blood flow. The interval between the R wave of the ECG and the first peak of WI (R-1st peak interval) and the interval between the first and second peaks (1st-2nd interval) are approximately equal to the preejection period and left ventricular ejection time, respectively. Using a combined Doppler and echo-tracking system, we obtained carotid arterial WI noninvasively. We examined the characteristics of WI in 11 patients with mitral regurgitation (MR) before and after surgery, and 24 normal volunteers. In the MR group before surgery, the second peak was decreased and the (1st-2nd interval)/(R-R interval) ratio was reduced, compared with the normal group (140 +/- 130 vs 750 +/- 290mmHg m/s3. P0.0083; 20.7% +/- 3.4% vs 26.7% +/- 2.8%, P0.083). There were no significant differences in the first peak between the normal group and the MR group before and after surgery. The second peak in the MR group was increased significantly (P0.016 vs before surgery) to 1,150 +/- 830mmHg m/s3 in the early period after surgery (stage I), and to 1,090 +/- 580mmHgm/s3 in the late period after surgery (stage II). These values did not differ significantly from that of the normal group. At stage I, the (R-1st peak interval)/ (R-R interval) ratio was increased from 13.4% +/- 2.7% to 20.6% +/- 5.6% (P0.016 vs before surgery). At stage II, this ratio decreased to 16.2% +/- 2.8% (P0.016 vs stage I). but was still significantly higher than that before surgery. The (1st-2nd interval)/(R-R interval) ratio increased significantly after surgery (P0.016 vs before surgery) to values (27.0% +/- 4.5% at stage I and 28.9% +/- 2.6% at stage II) which did not differ significantly from that of the normal group. The recovery of the second peak after surgery suggests that the left ventricle had recovered the ability to actively stop aortic blood flow. Wave intensity is useful for analyzing changes in the working condition of the heart.

To evaluate left ventricular function during exercise after aortic annular enlargement 15 patients with either aortic (group I, n = 8) or aortomitral (group II, n = 7) annuloplasty for small aortic annuli and eight patients (group III) with standard valve replacement for aortic stenosis without small aortic annuli received gated cardiac pool imagining by technetium-99m-labelled red blood cells at rest and during exercise at a mean of 23 months after operation. Left ventricular ejection fraction, preload requitable stroke work and stroke power index (preload requitable stroke work/systolic ejection period) were measured. Compared with resting values, left ventricular performance and stroke work rate on exercise after aortic annular enlargements increased significantly, as did those after standard aortic valve replacement. These results suggest that aortic annular enlargement can be indicated for surgical treatment of valvular heart diseases associated with small aortic annuli.

A patient with Stanford type A acute aortic dissection who developed severe cerebral dysfunction after surgery using retrograde cerebral perfusion through the superior vena cava was examined. The patient was able to regain normal brain function with no neurological deficit. Postoperative venography taken through the superior vena cava showed the presence of competent venous valves at the venous angles. This suggests that the valves interrupted cerebral perfusion, decreasing blood flow to less than that required. After consideration of the possible causes of brain damage incurred during surgery for aortic aneurysm using retrograde cerebral perfusion, it was concluded that this patient was able to recover normal brain function because the surgery was performed under profound hypothermia.

BACKGROUND JTV519 is know to protect cardiomyocytes from calcium overloading-induced damage. The aim of this study was to investigate the potential protective effect of JTV519 on myocardium subjected to prolonged ischemia and the underlying mechanism of such protection. The effect of JTV519 was also compared with that of diltiazem, a 1,5-benzothiazepine derivative. METHODS Isolated rat hearts were randomly divided into three groups. Control hearts were arrested with histidine-tryptophan-ketoglutarat (HTK) cardioplegic solution alone. In the JTV519 group of hearts, cardiac arrest was achieved with JTV519 (10(-3) mmol/L) in the HTK solution. Hearts in the diltiazem group were arrested with diltiazem (0.5 mmol/L) in the HTK solution. All the hearts were then subjected to 6-hour storage in HTK solution at 4 degrees C. RESULTS After a 30-minute reperfusion, the left ventricular developed pressure in the JTV519 and diltiazem groups were improved significantly compared with the control group. There was a significantly lower left ventricular end-diastolic pressure level and higher recovery of coronary flow in the JTV519 group than in the control group. The postischemic intracellular calcium concentration was attenuated by adding JTV519 or diltiazem to HTK cardioplegia. CONCLUSION As an adjunct to cardioplegia, JTV519 showed a significant protective effect on myocardium undergoing 6 hours of ischemia. The beneficial protective effects of JTV519 are correlated with its ability to inhibit the postischemic rise in intracellular calcium.

Angiogenesis by basic fibroblast growth factor (bFGF) is important for endothelialization in vascular prostheses and is significant from shortly after implantation. Canine adipose tissue was resected, minced into fragments, and suspended. This mixture was sieved through the wall of a fabric vascular prosthesis. Tissue-fragmented grafts (TF-grafts, 6 mm internal diameter, 6 cm long) were implanted into the abdominal aortae of four dogs, and four preclotted grafts were used as control subjects. Grafts were removed at 1-7 days after implantation. Removed grafts were evaluated microscopically, immunohistologically, and by scanning electron microscope. At day 1, a thrombus layer was on the TF-graft lumen. At day 3, cell proliferation and migration were observed. At day 5, endothelial-like cells were extending onto the luminal thrombus. Cell proliferation around the fragments was active, and those cells were bFGF positive. In the control subjects, at day 7, the perigraft tissue was bFGF positive, whereas no endothelialization on the lumen or no capillary infiltration into the graft wall was observed. Furthermore, bFGF was negative in the sites of thrombus and infection. These results demonstrate that endogenous bFGF is important for endothelialization due to angiogenesis in fabric vascular prostheses, whereas thrombus and infection might have a negative effect.

Background The leading cause of death in chronic renal dialysis patients is cardiovascular disease. As the number of dialysis patients increases, we are encountering more patients with severe ischemic heart disease requiring coronary intervention. Methods A retrospective analysis was performed of the short- and long-term clinical results in 23 coronary artery bypass grafting patients and 20 coronary angioplasty patients undergoing chronic renal dialysis. Results Among coronary bypass grafting patients, there were no hospital deaths. The graft patency rate was 100% for arterial grafts. There were four late deaths and four cardiac events. In coronary angioplasty patients, the lesion success rate was 76%. There were no hospital deaths and three major complications. The restenosis rate was 70%. There were two late deaths and 14 cardiac events. The 5-year cardiac event-free rate was 70% in coronary bypass grafting patients, significantly better than 18% in coronary angioplasty patients (p Conclusions Coronary artery bypass grafting in chronic renal dialysis patients can be accomplished with a better short- and long-term outcome than coronary angioplasty, through an intensive perioperative dialysis program and extensive use of arterial grafts.

We have used two techniques of hypothermic cerebral perfusion (CP) for the surgical treatment of aortic arch aneurysm in the last 10 years. Between March 1985 and December 1993, 83 patients underwent surgery for aortic arch aneurysm. Fifty-one cases had aortic dissection (AD) in the transverse arch and/or its branches, and 32 cases showed true aneurysm (TA) of the aortic arch. In those 83 patients, 37 cases received antegrade CP and 46 cases underwent retrograde CP. Surgical results were compared among the groups by Kaplan-Meier actuarial method and Cox-Mantel statistical analysis. The early mortality after surgery for aortic arch aneurysm was 11.8% in the AD group and 21.9% in the TA group. The early mortality was 21.6% with antegrade CP and 10.9% with retrograde CP. The 6-year actuarial survival rate was 71.7% in the TA group and 67.1% in the AD group. In the AD group, the 3-year survival rate was 93.9% with retrograde CP and 61.1% with antegrade CP (P< 0.005). In the TA group, the 3-year survival rate was similar for antegrade CP (73.3%) and retrograde CP (69.2%). These results suggest that current surgical results of aortic arch aneurysm with hypothermic CP are acceptable and the retrograde CP technique might be recommended, especially for surgery of aortic arch aneurysm with AD.

Twenty-three chronic renal dialysis patients underwent coronary artery bypass grafting (CABG). Eighteen patients were maintained on hemodialysis and 5 patients received continuous ambulatory peritoneal dialysis. Eighteen patients (78%) had triple vessel disease or left main disease. The mean number of revascularized vessels was 2.2 +/- 0.8, and the graft materials used were left internal thoracic artery (21), right internal thoracic artery (7), right gastroepiploic artery (7), and saphenous vein (15). The utilization index of arterial grafts (percentage of patients with at least one arterial graft) was 95.7%. Intraoperative hemodialysis (HD) was performed during cardiopulmonary bypass in all patients. In 17 patients on HD preoperatively, peritoneal dialysis (PD) was initiated immediately after the operation, and maintained until the hemodynamics stabilized sufficiently to resume HD (mean: 5.7 +/- 3.4 days after operation). In the patients with a gastroepiploic artery pedicle, PD could be established without leakage of dialysis fluid into the pericardial cavity by means of making a smaller hole in the diaphragm, passing the skeletonized portion of the graft through the hole and sealing the hole using fibrin glue. There were no hospital deaths. Angiography revealed an overall graft patency rate of 95.8% (46/48), and all arterial grafts were patent. There were 4 late deaths (1 cardiac, 3 cerebral hemorrhage). In conclusion, CABG can be accomplished in chronic renal dialysis patients with excellent early and long-term results through an intensive perioperative dialysis program and extensive usage of arterial grafts.