[A case of diffuse alveolar hemorrhage developing after open heart surgery]

A 47-year-old man was receiving anticoagulant therapy after coronary artery bypass grafting and mitral valve plasty. A chest roentgenogram disclosed alveolar infiltrates throughout both lung fields 6 months postoperatively. Lung biopsy specimens showed the presence of hemosiderin-laden macrophages in the alveolar spaces, establishing a diagnosis of diffuse alveolar hemorrhage. Anticoagulant therapy may have caused the hemorrhage, because the patient had no immunologic disorder or renal disease. The shadows completely disappeared after steroid therapy and discontinuation of anticoagulant therapy. Diffuse alveolar hemorrhage should be considered, when extensive infiltrates develop on chest roentgenogram in patients receiving anticoagulant therapy after open heart surgery. Lung biopsy is essential, when a bronchoalveolar lavage fails to diagnose the disease.

Balloon catheter for cyst aspiration in a thoracoscopic resection of mediastinal cysts

In a thoracoscopic resection of mediastinal cysts, aspiration of the cyst contents at the beginning of the procedure is often helpful because it allows the cyst to be more easily grasped and manipulated. Spillage of the cyst contents into the thoracic cavity may, however, occur during aspiration when an ordinary aspiration needle is used. If the cyst contents are infective, then a subsequent contamination of the thoracic cavity may develop. We therefore use a specially designed double-balloon catheter for aspiration to minimize spillage of the cyst contents into the thoracic cavity. We describe herein the usefulness of this aspiration technique.

Effect of a neutrophil elastase inhibitor (ONO-5046 Na) on ischemia/reperfusion injury using the left-sided heterotopic canine heart transplantation model

BACKGROUND

Ischemia/reperfusion injury is a major cause of transplanted heart dysfunction. Several reports have demonstrated that polymorphonuclear neutrophil (PMN) elastase derived from the activated neutrophils might play an important role in this injury. Herein, we investigated the protective effects of PMN elastase inhibitor (ONO-5046 Na) on ischemia/reperfusion injury using a left-sided canine heterotopic heart transplantation model.

METHODS

We used 10 pairs of adult beagle dogs. The donor heart was transplanted heterotopically into the left thoracic cavity of the recipient without cardiopulmonary bypass. A bolus of ONO-5046 Na (10 mg/kg) was introduced intravenously to 5 recipients (group II) at 15 minutes before reperfusion and was followed by continuous infusion (10 mg/kg per hour) for 180 minutes. Five dogs (group I) did not receive ONO-5046 Na and thus served as a control. After reperfusion, we evaluated transplanted heart function and obtained blood samples from the coronary sinus over a 360-minute period.

RESULTS

E(max) and pre-load recruitable stroke work in group II showed significantly better recovery than group I. Blood levels of PMN elastase, creatine kinase MB, lactate and inflammatory cytokines (tumor necrosis factor-alpha, interleukin-6, interleukin-8) were significantly lower in group II. Depletion of myocardial concentration of adenosine triphosphate at 120 minutes after reperfusion and myocardial water content was significantly lower in group II.

CONCLUSIONS

ONO-5046 Na, which inhibits PMN elastase, could reduce ischemia/reperfusion injury in heart transplantation. These results indicate that clinical application of ONO-5046 Na should be considered.

Coronary artery bypass grafting for dialysis patients. Effects of cardiopulmonary bypass

OBJECTIVE

To assess the efficacy and safety of cardiopulmonary bypass during coronary artery bypass grafting (CABG) in dialysis patients.

METHODS AND RESULTS

Sixty four isolated CABG patients who underwent on cardiopulmonary bypass and whose intraoperative body weight gains were accurately measured were studied retrospectively. The mean intraoperative body weight gain was 2.61 +/- 0.9 kg/m2 in the study group and 1.06 +/- 0.6 kg/m2 in controls, i.e.) 100 patients selected at random from CABG patients during the same period using cardiopulmonary bypass without chronic renal faulure, showing a statistically significant difference. Complete revascularization was successful in 98% of patients. Postoperative nonlethal complications involved brain infarction in 1 patient (1.7%), reintubation in 1 (1.7%), and paralytic ileus in 2 (3.4%). All were successfully extubated within 24 hours of surgery, and no sternal wound complications were found. Hospital mortality was 6.3% (4/64). Actuarial survival rates at 3, 5 and 8 years including all deaths were 90%, 70% and 56%, and estimated by cardiac deaths were 95%, 90%, and 90% respectively. Cardiac event free rates were 90%, 73% and 61% at 3, 5 and 8 years after CABG.

CONCLUSIONS

In CABG for dialysis patients, the use of cardiopulmonary bypass demonstrates significant merits, and may expect long-term survival with minimal postoperative complications.

Contribution of serotonin to liver injury following canine small-intestinal ischemia and reperfusion

Intestinal ischemia and reperfusion (I/R) has been shown to be associated with multiple organ damages. Serotonin (5-hydroxytriptamine; 5-HT), which is synthesized in the enterochromaffin cells in the intestine and stored in platelets, is known to play an important role in platelet aggregation and vasoconstriction and may ultimately enhance such organ injuries. The purpose of this study was to investigate the association between liver damage and 5-HT levels in the liver after intestinal I/R. The entire canine small intestine, isolated on a vascular pedicle that consisted of the proximal superior mesenteric artery and superior mesenteric vein, was subjected to 4-h ischemia by clamping these vessels and the marginal arteries supplying the proximal and distal ends of the small intestine. Hepatic blood flow, liver tissue blood flow, bile flow rate, and hepatic venous ketone body ratio (HVKBR) were measured before and at the end of intestinal ischemia and at 5, 15, and 30 min, and 1 and 2 h after reperfusion. 5-HT levels in plasma of the portal vein and hepatic vein were assayed at the same intervals. Time-matched, sham-operated animals served as controls. Intestinal I/R significantly decreased the liver tissue flow, bile flow rate, and HVKBR. Compared to those in controls, 5-HT levels in the portal vein and hepatic vein were markedly increased after reperfusion. Furthermore, intravenous administration of 5-HT receptor antagonists attenuated the liver dysfunction after intestinal reperfusion. These results suggest that intestinal I/R induces continuous disturbance of hepatic microcirculation, leading to liver dysfunction, and that 5-HT may be implicated as one of the mediators of liver dysfunction after intestinal I/R.

Early results and characteristic problems associated with cardiac surgery in long-term dialysis patients

OBJECTIVE(S)

To analyze early results and characteristic problems that develop after cardiac surgery on dialysis patients.

METHODS

One hundred fourteen patients on maintenance dialysis underwent cardiac surgery. Their mean age was 63.5 +/- 9.7 years, and 87 (76%) were male. The causes of chronic renal failure were diabetes mellitus in 41 (36%) and chronic glomerulonephritis in 40 (35%). Patients had previously been on dialysis for a mean duration of 7.8 +/- 5.6 years (range; 0.25-24 years).

RESULTS

Fourteen (12%) were emergent cases. Eighty six patients (75%) received isolated coronary artery bypass grafting (CABG), and 10 patients underwent operations in which CABG was combined with other cardiac procedures. Twelve patients (14%) of the isolated CABG patient group (86 patients) were restricted to non-clamping bypass procedure due to severe calcification of the ascending aorta. Calcification score, which was represented by the sum of all involved coronary artery segments, was also significantly higher in dialysis patients than in the control group (4.5 +/- 2.4 segments vs. 1.5 +/- 2.1 segments, p < 0.05). Hospital mortality was 8.8% (10/114) overall, and 7% (6/86) in isolated CABG patients. The causes of deaths were as follows: intestinal necrosis in 3, arrhythmia in 2, cerebral infarction in 1, low output syndrome in 1, and sepsis in 3 (mediastinitis, pneumonia, and prosthetic valve infection).

CONCLUSIONS

Long-term dialysis is a major risk factor in cardiac surgery. However, because the surgical results proved to be acceptable, long-term dialysis patients should not be denied cardiac surgery.

Effects of sarpogrelate hydrochloride on adenosine diphosphate- or collagen-induced platelet responses in arteriosclerosis obliterans

To evaluate the effects of the 5-HT2 receptor antagonist sarpogrelate hydrochloride (sarpogrelate) on platelet responses in arteriosclerosis obliterans (ASO), we examined platelet aggregation and its relationships to platelet-derived growth factor (PDGF), soluble P-selectin (sP-selectin), and transforming growth factor-beta 1 (TGF-beta1). Circulating plasma levels of PDGF and sP-selectin in 13 patients with ASO after 1 week of medication with sarpogrelate were significantly lower than those before medication. In contrast, circulating plasma levels of TGF-beta1 after medication were significantly higher than those before medication. When platelet-rich plasma obtained from ASO patients after medication was stimulated with adenosine diphosphate (ADP) or collagen, platelet aggregation was suppressed compared with rates before medication. Significant decreases in levels of PDGF, sP-selectin and TGF-beta1 released from platelets in response to 5 micromol/l ADP and 1 microg/ml collagen after taking of sarpogrelate were found. There were close correlations between platelet aggregation and respective molecules released from platelets. In conclusion, since platelet activation is involved in pathogenesis of thrombotic disease, sarpogrelate may suppress the development of obstructive arteriosclerosis. PDGF and TGF-beta1, as well as sP-selectin, appear to be useful markers for clinical evaluation of anti-platelet drugs.

One-stage thoracic aortic aneurysm treatment and coronary artery bypass grafting

OBJECTIVE

The treatment of thoracic aortic aneurysm accompanied by ischemic heart disease presents a surgical challenge and has up to now shown a high hospital mortality rate. This report discusses the factors contributing to improved results in these cases.

METHODS

We conducted a retrospective analysis of the records of 24 consecutive patients who had undergone replacement of thoracic aorta with combined coronary artery bypass grafting (CABG) between May 1991 and October 1998. Fifteen patients received total arch replacement (Arch-with-CABG Group), and the other 9 patients received the Bentall operation (Bentall-with-CABG Group). These results were compared with those patients who had undergone replacement of the thoracic aorta without CABG (Without-CABG Group).

RESULTS

In the combined CABG groups, the overall operative mortality rate was 16.7%. In comparison with the Arch-without-CABG Group, there was a significantly longer cardiopulmonary bypass time and longer selective cerebral perfusion time in the Arch-with-CABG Group. However, no significant difference was observed in postoperative complications between the two groups. In addition, there was no significant difference in either actuarial survival or the cardiac-event-free rate at 5 years between the replacement of thoracic aorta with- and without-CABG Groups (83.1% vs. 90.4%, and 78.5% vs. 77.7%, respectively). No reoperation and no late death were observed during the follow-up period (mean 21.3 months).

CONCLUSIONS

We concluded that replacement of the thoracic aorta combined with CABG can be carried out safely, and that revascularization for coronary artery disease is useful for preventing any occurrence of cardiac event.

A leukocyte depleting filter reduces endothelial cell dysfunction and improves transplanted canine heart function

BACKGROUND

To date leukocytes have been known to play a major role in reperfusion injury and have directed attention to leukocyte-endothelium interaction. This study was designed to investigate how much graft viability and the coronary microcirculatory function could be preserved by leukocyte depletion (LD) in a model of orthotopic cardiac transplantation.

METHODS

The heart in 10 beagle dogs was arrested by introducing a 4 degrees C St. Thomas' cardioplegic solution. They were harvested, immersed in the cold saline for 3 hours, and then orthotopically transplanted. Five recipients underwent LD (LD group) at reperfusion with the use of a Pall BC1B leukocyte depleting filter inserted into the cardiopulmonary bypass (CPB) circuit. The other 5 dogs without filtration served as a control group.

RESULTS

Leukocytes were about 80% filtrated and neutrophils were also 85% filtrated during the first 30 minutes of reperfusion in the LD group. A high level of adenosine triphosphate was maintained after transplantation in the LD group. The polymorphonuclear elastase level was significantly lower in the LD group. The cardiac function assessed by the slopes of the end-systolic pressure volume relation after transplantation was significantly higher in the LD group than in the control group (p < 0.05). The coronary vascular resistance responses to acetylcholine and nitroglycerin after transplantation were preserved significantly better in the LD group than in the control group (p < 0.05).

CONCLUSIONS

These results suggest that a leukocyte depleting filter placed in the CPB circuit would prevent leukocyte-mediated endothelial cell injury, improve microcirculation of the myocardium, and lead to excellent graft function.

Estrogen upregulates nitric oxide synthase expression in cultured rat hepatic sinusoidal endothelial cells

BACKGROUND/AIMS

Estrogen receptor (ER) is present in vascular endothelial cells and estrogen promotes nitric oxide (NO) synthesis, which relaxes smooth muscle cells. It is also speculated that NO is synthesized by estrogen in hepatic sinusoidal endothelial cells (SECs). Here we investigated the localization of ER and endothelial cell nitric oxide synthase (ecNOS), and determined 17beta-estradiol (E2)-induced ecNOS expression in normal rat SECs.

METHODS

Cultured SECs were used. Fluorescence intensities of ecNOS were measured by immunofluorescence using a confocal laser-scanning microscope. E2 was added (100 pg/ml) to the culture medium, and the expressions of ecNOS mRNA and protein were analyzed by reverse-transcription polymerase chain reaction and Western blotting. NO production in cultured SECs was examined using diaminofluorescein-2 diacetate as a fluorescent indicator for NO.

RESULTS

Immunolocalization of ER and ecNOS in normal liver was demonstrated in endothelial cells lining the hepatic sinusoids. ER and ecNOS were localized in the nuclei and cytoplasm of cultured SECs, respectively. The mRNA expression of ecNOS in cultured SECs was increased after 6 h, and the protein expression of ecNOS was increased 24 h after E2 stimulation. The fluorescence intensity of NO in cultured SECs was increased by E2 stimulation compared with untreated control cells.

CONCLUSIONS

These results suggested that ER is present in SECs, and estrogen upregulates NO production in SECs. E2 may be involved in the regulation of the hepatic sinusoidal microcirculation.

Technical aspects and outcome of in situ right internal thoracic artery grafting to the major branches of the circumflex artery via the transverse sinus

BACKGROUND

Little is known about the anatomic limitations of in situ right internal thoracic artery (RITA) grafting to the circumflex artery.

METHODS

To evaluate the technical aspects and outcome of revascularization of the proximal and distal major branches of the circumflex artery (obtuse marginal [OM] branch and posterolateral [PL] branch), a total of 145 patients who possessed a graftable branch of the circumflex artery were enrolled into the prospective project. There were 73 patients who had the PL branch as a primary target and 72 patients with OM branches, which were allocated by a blinded observer who reviewed the preoperative angiography.

RESULTS

Changes of primary target vessels were required in 9 patients (6.2%), yielding an overall success rate of RITA grafting of 93.8%. The success rates of RITA grafting to the OM branch and the PL branch were 95.8% (69/72; CI 88.3% to 99.1%) and 91.7% (67/73; CI 83.0% to 96.9%), respectively. The univariate analysis identified grafting under hypothermic ventricular fibrillation as predictors of inability to use in situ RITA grafting for revascularization of the circumflex artery. RITA grafting to the PL branch is not identified as a predictor. Postoperative angiography in 136 patients revealed only one occlusion (0.75%) of the RITA graft anastomosed to the marginal artery. There were no significant differences in patency rates between left and right ITA grafts.

CONCLUSIONS

This prospective study showed that in situ RITA was, in most cases, able to reach most branches of the major circumflex artery and demonstrated an excellent patency rate.

Evaluation of carriers of bone morphogenetic protein for spinal fusion

STUDY DESIGN

Posterolateral lumbar transverse process fusion in a rabbit model was performed using two different carriers for recombinant human morphogenetic protein-2, one having a porous structure and the other being a Type I collagen sheet.

OBJECTIVES

To compare the effectiveness of two different carriers for recombinant human morphogenetic protein-2 in achieving lumbar intertransverse process arthrodesis.

SUMMARY OF BACKGROUND DATA

The application of osteoinductive growth factors at various anatomic sites, such as in long bones and spinal segments, has been performed experimentally by many researchers. Although many carriers of osteoinductive factors have been reported, the most effective carrier has not been established. We have reported the efficacy of sintered bovine bone, True Bone Ceramics, which is coated with Type I collagen as a carrier of recombinant human bone morphogenetic protein-2 in achieving lumbar intertransverse process arthrodesis. True Bone Ceramics is a crystallized form of bone minerals made from sintering bovine bone at high temperatures and possesses natural trabecular structure. The crystalline character of True Bone Ceramics is similar to that of artificial hydroxyapatite. In this study we focused on the structure of two different carriers to facilitate osteosynthesis in lumbar arthrodesis.

METHODS

Fifty-four adult rabbits underwent bilateral lumbar intertransverse process arthrodesis at L4-L5. The animals were divided into five groups and had implants placed as follows: Group 1, autograft group, harvested autologous corticocancellous bone from the posterior iliac crest; Group 2, TBC group, True Bone Ceramics alone; Group 3, TBC-TBMP group, True Bone Ceramics coated with Type I collagen infiltrated with 100 microg of recombinant human bone morphogenetic protein-2; Group 4, collagen group, Type I collagen sheet; and Group 5, collagen-BMP group, implanted collagen sheet containing 100 microg of recombinant human bone morphogenetic protein-2. Spinal fusion was evaluated by radiographic analysis, manual palpation, biomechanical testing, and histologic examination at both 3 and 6 weeks after surgery.

RESULTS

Radiographs in the TBC-TBMP group showed a continuous trabecular pattern within the intertransverse area at 3 weeks after surgery. The fusion mass in the intertransverse area was more prominent than in the other groups. At 3 weeks after surgery the TBC-TBMP group had higher fusion rates based on manual palpation, and the fusions showed significantly higher tensile strength and stiffness. The histologic findings in the TBC-TBMP group at 3 weeks after surgery showed a cortical bone rim around the edge of the fusion mass, and contiguous new bone appearing between the recipient bone and the matrix of TBC without evidence of foreign body formation. In the collagen-BMP group, less mature bone formation was present within the grafted area and the new bone was not contiguous, even at 6 weeks after surgery.

CONCLUSIONS

As a carrier for recombinant human bone morphogenetic protein-2, True Bone Ceramics, possessing a bony or porous structure, was more effective than a Type I collagen sheet in achieving a faster and stronger lumbar spinal fusion in a rabbit model.

Coronary artery bypass grafting for dialysis patients: usefulness of multiarterial bypass

This study assessed the efficacy of multiarterial bypass in coronary artery bypass grafting (CABG) in dialysis patients. Eighty dialysis patients who underwent CABG were divided into 2 groups. Group A consisted of 38 patients in whom the left internal thoracic artery and additional saphenous vein graft (SVG) had been used. Group B consisted of 42 patients in whom 2 or 3 arterial grafts and additional SVGs had been used. No mediastinitis was shown in either group. Actuarial survival rates, including all deaths, and estimated by cardiac deaths at 8 years, were 28% and 83%, respectively, in Group A and 93% and 100%, respectively, in Group B with a significant difference (p = 0.014 and 0.016, respectively). Cardiac event-free rates at 8 years were 43% and 96% in Groups A and B, respectively, with a significant difference (p = 0.0016). Multiarterial grafting improved long-term results after CABG for dialysis patients compared with single internal thoracic artery grafting with minimal complications related to graft harvesting.

Double left renal vein associated with abdominal aortic aneurysm

Double left renal vein is a rare venous anomaly. We operated on 72-year-old man of abdominal aortic aneurysm (AAA) with double left renal vein. Massive hemorrhage was encountered during encircling the tape around the abdominal aorta. One vein passing posterior to the aorta was injured. Further dissection revealed the presence of double left renal vein forming a ring around the aorta. The patient underwent an abdominal aortic replacement following prompt repair of the injured vein. He had an uneventful postoperative course without renal complication. We missed that preoperative computed tomographic (CT) scan had demonstrated double left renal vein. Preoperative contrast-enhanced CT scan is useful and essential not only for evaluation of AAA, but also for establishing the presence of venous anomalies. Venous anomalies should be taken into consideration on the AAA operation.

Inhibition of platelet aggregation and the release of P-selectin from platelets by cilostazol

To evaluate the in vitro effects of cilostazol, a phosphodiesterase III inhibitor, on platelet responses, we measured platelet aggregation and the levels of soluble P-selectin, a glycoprotein present on the alpha-granule membrane in resting platelets, and cAMP. Platelet-rich plasma and washed platelets from healthy human volunteers were treated with cilostazol (5, 25 and 50 microM). Platelet-rich plasma was stimulated by ADP (1 and 5 microM) or collagen (5 microg/ml). Washed platelets were stimulated by thrombin (4 U/ml) in the presence or absence of 1 microM forskolin. In vehicle-treated samples, soluble P-selectin levels in response to 1 microM ADP-induced primary aggregation were similar to those of circulating levels of healthy volunteers but the levels in response to 5 microM ADP-induced secondary aggregation and collagen-induced aggregation increased markedly compared to those in response to primary aggregation. This result suggests that P-selectin is released from platelets according to the extent of platelet aggregation. Cilostazol inhibited platelet aggregation as well as P-selectin release in a concentration-dependent manner. Cilostazol inhibited completely thrombin-induced aggregation in the presence of 1 microM forskolin, when cAMP levels were two-fold higher than those in the absence of forskolin. Cilostazol, which increases intracellular cAMP in platelets, may be useful in the treatment of arterial occlusive diseases.

Necessity of monitoring HPLC by a X-R control chart on measurement of serum fat-soluble vitamins

In epidemiologic studies, many serum samples obtained from a large population have to be processed for measurement of fat-soluble vitamins. Quantification results by a high performance liquid chromatography (HPLC) should be stable in both intra- and inter-run, and a quality control may be performed by a X-R control chart. The present study shows that serum retinol, alpha-tocopherol, alpha-carotene, beta-carotene, and lycopene could be measured simultaneously, by 1) use of photodiode-array (POD) detector, 2) selection of some optimal analytical conditions (e.g. column, mobile phase, column temperature), 3) applying 2 internal standards, and 4) monitoring by a X-R control chart. The present procedure yielded relatively low coefficients of variations (CVs) compared to some reported figures. However, determination of CVs only does not ensure the accuracy and precision of an assay system, and application of a X-R control chart may be necessary for a good quality control of measurement, such as serum fat-soluble vitamins.

Bilateral internal thoracic artery use for dialysis patients: does it increase operative risk?

BACKGROUND

The efficacy and risk of using the bilateral internal thoracic artery (BITA) for coronary artery bypass grafting in dialysis patients is virtually unknown.

METHODS

Twenty-five patients on dialysis who underwent coronary artery bypass grafting using the BITA were retrospectively studied (BITA group). For comparison purposes, 52 patients on dialysis who underwent coronary artery bypass grafting using the left ITA were selected (LITA group).

RESULTS

No wound healing problems occurred in the BITA group. Mean postoperative bleeding volume was 1,427 +/- 808 mL and 800 +/- 508 mL in the BITA and LITA groups, respectively (p = 0.00009). Blood transfusions for the BITA and LITA groups required an average of 6.8 and 6.2 units of packed red blood cells, respectively, with no significant difference. Five patients in the BITA group (20%) showed severe atherosclerotic deterioration of the ascending aorta, precluding clamping. Hospital mortality was 4% (1 of 25 patients) in the BITA group and 7.7% (4 of 52 patients) in the LITA group, with no significant difference (p = 0.49).

CONCLUSIONS

In patients on dialysis, especially those with severe atherosclerotic or calcified deterioration of the ascending aorta, coronary artery bypass grafting using BITA grafting (arterial in situ conduits) may offer the easiest and most suitable solution without increased operative risk.

Hes7: a bHLH-type repressor gene regulated by Notch and expressed in the presomitic mesoderm

BACKGROUND

Whereas Notch signalling is essential for somitogenesis, mice deficient for the basic helix-loop-helix (bHLH) genes Hes1 and Hes5, downstream Notch effectors, display normal somite formation, indicating that there may be an as-yet unidentified Hes1-related bHLH gene.

RESULTS

We identified a novel bHLH gene, designated Hes7, from mouse embryos. Hes7 has a conserved bHLH domain in the amino-terminal region and the WRPW domain at the carboxy-terminal end, like Hes1. The mouse Hes7 gene is located next to Aloxe3, which is mapped to a position 37.0 cM from the centromere on chromosome 11. In a transfection analysis, Hes7 represses transcription from the N box- and E box-containing promoters. In addition, Hes7 suppresses the E47-induced transcriptional activation. Promoter analysis indicated that Hes7 expression is controlled by Notch signalling. Strikingly, Hes7 is specifically expressed in the presomitic mesoderm in a dynamic manner. We also identified two related bHLH genes from human: one is closely related to mouse Hes7 and therefore designated hHes7 and the other designated hHes4.

CONCLUSION

The structure, transcriptional activity and expression pattern in the presomitic mesoderm of Hes7 are very similar to those of Hes1, suggesting that Hes7, together with Hes1, may play a role in somite formation under the control of Notch signalling.

The impact of chronic renal failure on atherosclerosis of the internal thoracic arteries

BACKGROUND

Little is known about the impact of renal failure on atherosclerotic changes in the internal thoracic artery (ITA).

METHODS

A total of 20 consecutive patients on chronic dialysis who underwent coronary artery bypass grafting (CABG) during April 1998 through September 1999 were investigated. The 20 control patients were selected from the same interval to rigorously match risk factors. Atherosclerosis of the ITA collected from each patient was analyzed using the subjective evaluation proposed by Kay and colleagues.

RESULTS

There were no cases of greater than 25% atherosclerotic luminal narrowing among a total of 35 ITA specimens from dialysis patients. The degree of atherosclerosis was not significantly different from that of the specimens from matched patients (p = 0.18). No calcification was found in ITA grafts either microscopically or macroscopically. The number of elastic lamellae, an index of the elasticity of the ITA graft, was not significantly different from those obtained from the matched patients. Analysis of preoperative coronary angiography revealed that coronary calcification was significantly more frequent in dialysis patients (15 patients, 75%) than in matched patients (p < 0.05). By analysis of postoperative angiography in dialysis patients, no evidence of atherosclerotic changes was found in 28 opacified ITAs. In addition, despite the presence of calcification in the native coronary, no calcification was evident along the entire length of the ITAs.

CONCLUSIONS

This study revealed the minimal impact of chronic renal failure on atherosclerotic changes in the ITA. The results of this study support the continued use of ITA grafting in dialysis patients.

Relation of type II transforming growth factor-beta receptor to hepatic fibrosis and hepatocellular carcinoma

Hepatocarcinogenesis is closely related to hepatic fibrosis. In this study, we investigated the relationship of type II transforming growth factor-beta receptor (T beta RII) to hepatic fibrosis and hepatocellular carcinoma (HCC). In vivo: liver tissues were obtained from 30 patients (10 chronic hepatitis, 7 cirrhosis, 13 HCC). Protein expression and immunolocalization of T beta RII were examined by Western blot analysis and immunohistochemistry. In vitro: T beta RII protein expression in hepatoma cell lines (HepG2, Hep3B, HLE, HLF and Huh7) was examined by Western blot analysis. Next, we transfected T beta RII cDNA to Huh7, and compared the change of cell number and observed the induction of apoptosis after TGF-beta1 treatment using a FACScan flow cytometer. In vivo: T beta RII immunolocalization in liver tissues was significantly decreased in patients with HCC compared with that of patients with chronic hepatitis or liver cirrhosis. In Western blot analysis, T beta RII expression in tissues attenuated in comparison with that in non-tumor tissues in some patients with HCC. In vitro: T beta RII protein expression in HLE, HLF and Huh7 cells was weaker than that in HepG2 and Hep3B cells. In Huh7 cells transfected T beta RII cDNA, cell arrest and apoptosis were obviously induced. These results indicated that human HCC has a reduced expression of T beta RII for TGF-beta1. This may provide a selective growth advantage to HCC to escape the inhibitory growth signals of TGF-beta1, and may be linked with critical steps in the growth of hepatoma cells.

Growth potential of left internal thoracic artery grafts: analysis of angiographic findings

BACKGROUND

The growth potential of the internal thoracic artery (ITA) is still undetermined, and little is known about the long-term effects of anastomosing it to the coronary artery.

METHODS

Fifty-three patients whose left ITA (LITA) had been anastomosed to the left anterior descending (LAD) coronary artery underwent coronary angiography within 1 month of operation and in late follow-up (mean interval: 4.5 +/- 1.5 years). The diameter ratios of LITA to LAD were designated as the matching ratio.

RESULTS

In follow-up, the diameter of the LITA increased from 1.83 +/- 0.40 to 2.46 +/- 0.53 mm in the 29 patients with progressive proximal native coronary stenosis. However, late results indicate that the matching ratio did not vary according to the location of the LITA anastomosis on the LAD (proximal portion: 1.13 +/- 0.16, distal portion 1.19 +/- 0.13), and reached an upper limit of about 1.4.

CONCLUSIONS

Growth potential of the LITA is limited by the diameter of the coronary artery onto which it is anastomosed. The most effective procedure for enhancing the growth potential of the LITA is to anastomose as proximally as possible onto the LAD.

[Surgical treatment for malignant pleural mesothelioma in eight cases]

Between 1987 and March 2000, we have operated on eight patients for malignant mesothelioma which consisted of four of localized type and four of diffuse type. We have aggressively resected mesothelioma combined with chemotherapy whether the tumor was primary or recurrent, and concluded the following. 1) In localized malignant mesothelioma, en-bloc primary tumor resection was possible and additional resection for recurrence was effective and useful for long time survival. 2) In diffuse malignant mesothelioma, complete tumor resection was impossible to even perform pleuropneumonectomy accompanied with partial resection of pericardium and diaphragm and, therefore, the prognosis was poor in four patients and all died around one year. 3) Because recurrent pattern for localized type was diffuse type, diagnosis and surgical treatment in early stage was essential for long time survival.

Long-term results of bilateral internal thoracic artery grafting

BACKGROUND

Little is known about the long-term results of the uniform group of patients who had bilateral internal thoracic artery (ITA) grafting with the method of left ITA-to-left anterior descending coronary artery and right ITA-to-circumflex artery.

METHODS

Late follow-up study was performed in the first consecutive 203 patients (mean age, 62.6 +/- 9.1 years) who underwent isolated coronary artery bypass grafting with the left ITA anastomosed to the left anterior descending coronary artery and the right ITA to major branches of the circumflex artery. The patients were grouped according to the patency of ITA grafts demonstrated by early postoperative angiography (Both patent (BP) group, 168 patients: both ITAs showed complete patency; Not patent (NP) group, 23 patients: at least one ITA was dysfunctional).

RESULTS

Actuarial 7-year survival in all patients was 89.3% +/- 3.1%. The cumulative probability of event-free survival for cardiac death, myocardial infarction, intervention, and angina at 7 years was 96.6% +/- 1.8%, 98.0% +/- 1.5%, 86.7% +/- 3.2%, and 90.7% +/- 2.9%, respectively. NP group had more myocardial infarction and angina than the BP group, but was not statistically significant. Because of failed grafts at the early angiography, intervention was performed more frequently in NP group (p < 0.01).

CONCLUSIONS

Our results of actuarial 7-year survival and the cumulative probability of event-free survival were at least comparable to the results of other similar studies using bilateral ITA. The freedom from angina appeared to be better than in the previous study. Overall our study supports the continued use of this method of ITA grafting.

Complete revascularization of the left anterior descending coronary artery

OBJECTIVE

To assess the efficacy of complete revascularization of the left anterior descending coronary artery.

METHODS

To obtain such revascularization, 81 patients required the use of such complex techniques as the onlay patch technique or double bypasses during bypass grafting.

RESULTS

The onlay patch technique was used in 39 (48%) and double bypasses in 42 (52%). The wall motion in all anterior segments of the left ventricle showed an improving trend postoperatively. The patency rate was 99% overall, and the bypass grafts to the left anterior descending coronary artery were all patent with flow in all left anterior descending coronary artery areas. Perioperative myocardial infarction occurred in only 1 patient (1.2%), and hospital mortality was 2.5% (2/81). Long-term results of 79 hospital survivors were as follows: the mean follow-up time was 77 months (3 to 236); the actuarial survival rate including all deaths and estimated by cardiac death was 90% and 95% at the eighth postoperative year respectively; the cardiac event free rate at the fifth and eighth postoperative year was 90% and 63% respectively. A total of 8 cardiac events were observed. Excluding 3 cardiac deaths, no cardiac events were clearly attributable to the left anterior descending coronary artery.

CONCLUSIONS

Complete revascularization of the left anterior descending coronary artery using these techniques improved the anterior wall motion in the left ventricle and cardiac performance at low risk, and provided excellent long-term results.

Inhibition of transforming growth factor beta prevents progression of liver fibrosis and enhances hepatocyte regeneration in dimethylnitrosamine-treated rats

We investigated whether anti-transforming growth factor beta (TGF-beta) molecular intervention can halt the progression of liver fibrosis in rats. To block TGF-beta action in a specific manner, we prepared an adenovirus expressing a truncated type II TGF-beta receptor (AdTbeta-TR), which specifically inhibits TGF-beta signaling as a dominant-negative receptor. We also used an adenovirus expressing bacterial beta-galactosidase (AdLacZ) as a control adenovirus. Rats were treated with dimethylnitrosamine (DMN) for 3 weeks; then, AdTbeta-TR, AdLacZ, or saline was intravenously applied once, followed by an additional 3-week DMN treatment. The ratio between the truncated receptor and the wild-type receptor at the mRNA level was 15 at 1 week and 10 at 3 weeks after gene transfer. Immunohistostaining analysis showed that the truncated receptor was expressed mainly in septal cells including hepatic stellate cells. Liver fibrosis, as assessed by histology, hydroxyproline content, and the serum level of hyaluronic acid, progressed during the additional 3-week DMN treatment. However, in rats infected with AdTbeta-TR, the fibrosis remained at the level seen in rats given DMN for only 3 weeks. All AdTbeta-TR-treated rats remained alive, whereas DMN-treated rats infused with either AdLacZ or saline died of liver dysfunction. In the livers of AdTbeta-TR-treated rats, electron microscopy showed: 1) less accumulation of extracellular matrix proteins in the Disse's spaces; 2) regenerated hepatocytes; and 3) fat droplet-rich "quiescent" hepatic stellate cells. Our results demonstrate that TGF-beta plays a critical role in the progression of liver fibrosis, and suggest that anti-TGF-beta intervention should be therapeutic in already-established fibrotic livers, not only by suppressing fibrosis, but by facilitating hepatocyte regeneration.