Cardiac troponin I is modified in the myocardium of bypass patients.

BACKGROUND: Selective proteolysis of cardiac troponin I (cTnI) is a proposed mechanism of contractile dysfunction in stunned myocardium, and the presence of cTnI degradation products in serum may reflect the functional state of the remaining viable myocardium. However, recent swine and canine studies have not demonstrated stunning-dependent cTnI degradation. METHODS AND RESULTS: To address the universality of cTnI modification, myocardial biopsy samples were obtained from coronary artery bypass patients (n=37) before and 10 minutes after removal of cross-clamp. Analysis of biopsy samples for cTnI by Western blotting revealed a spectrum of modified cTnI products in myocardium both before and after cross-clamp, including degradation products (7 products resulting from differential N- and C-terminal processing) and covalent complexes (3 products). In particular, a 22-kDa cTnI degradation product with C-terminal proteolysis was identified, which may represent an initial ischemia-dependent cTnI modification, similar to cTnI(1-193) observed in stunned rat myocardium. Although no systematic change in amount of modified cTnI was observed, subgroups of patients displayed an increase (n=10, 85+/-5% of cTnI remaining intact before cross-clamp versus 75+/-5% after) or a decrease (n=12, 67+/-5% before versus 78+/-5% after). Electron microscopy demonstrated normal ultrastructure in biopsy samples, which suggests no necrosis was present. In addition, cTnI modification products were observed in serum through a modified SDS-PAGE methodology. CONCLUSIONS: cTnI modification, in particular proteolysis, occurs in myocardium of bypass patients and may play a key role in stunning in some bypass patients.

Reconstruction of the left ventricle with autologous pericardium.

Autologous pericardium was used to reconstruct different parts of the left ventricle in 25 desperately ill patients. Fourteen patients had intractable sepsis resulting from infective endocarditis and myocardial abscess and 10 patients had noninfectious disorders. Of the patients with infections, 12 had valvular endocarditis with periannular abscess and three had interventricular septal abscess. The noninfected patients had acute rupture of the ventricular wall after mitral valve replacement (one patient) heavily calcified or surgically absent mitral anulus (three patients), or rupture of the interventricular septum after acute myocardial infarction (six patients). The interventricular septum, the posterior wall of the left ventricle, and the periannular areas were reconstructed by suturing appropriately tailored pericardial patches directly to the endocardium. In patients who also required valve replacement, the prosthetic valve was partially or completely secured to the pericardial patch. There were three operative deaths. All three patients were in either septic or cardiogenic shock before operation and in none of them was the death related to the pericardial patch. All 22 survivors have been observed from 3 to 34 months, an average of 14 months. There has been no case of patch dehiscence, patch aneurysm, prosthetic valve dehiscence, or recurrent endocarditis. Autologous pericardium appears to be safe for reconstruction of the left ventricle. It is easy to handle and problems with suture line bleeding are practically nonexistent.

Salvage of ischemic myocardium by nonsynchronized retroperfusion in the pig.

Salvage of ischemic myocardium, with the aid of a nonsynchronized coronary sinus retroperfusion system, was studied in a pig infarct model. In anesthetized open chested animals, the left anterior descending coronary artery was occluded for 4 hours and then reperfused for 1 hour before the animals were killed. In the control group (n = 12) no therapy was used. In the experimental group (n = 13), nonsynchronized retrovenous coronary sinus perfusion was applied during the 4 hours of coronary artery occlusion. Therapy consisted of intermittent balloon occlusion of the coronary sinus (5-second inflation, 5-second deflation) with retroperfusion of arterial blood at 60 ml/min during the inflation part of the cycle. Infarct size, expressed as a percentage of the area at risk (+/- standard deviation), was significantly smaller in the experimental group (41.5% +/- 15.0%) than in the control group (80.5% +/- 6.1%) (p less than 0.001). Mean coronary sinus pressure (+/- standard deviation) was 51 +/- 12 mm Hg in the experimental group but was not elevated in the control animals. We conclude that nonsynchronized retrovenous coronary sinus perfusion was able to significantly salvage ischemic myocardium in a model of minimal intercoronary collateral circulation.

Aortic dissection and use of the nicotine patch: a case involving a temporal relationship.

A 33-year-old woman presented with chest and abdominal pain shortly after first and second applications of the nicotine patch. Type A aortic dissection was diagnosed and repaired. Pathological examination revealed cystic medial necrosis, subacute and acute dissection, with no evidence of chronic aortic insufficiency. The close temporal relationship between applications of the nicotine patch and onset of symptoms compatible with dissection followed by extension raises the possibility that the nicotine patch was implicated in, or precipitated, this woman's aortic dissection.

Anomalous right coronary artery: a multimodality hunt for the origin.

Anomalous origin of the right coronary artery from the pulmonary artery (ARCAPA) is a rare congenital anomaly. Although there have been several cases of ARCAPA reported in the literature, we present a case which highlights the challenges of diagnosing this rare condition and the incremental value of using multiple imaging modalities. A healthy 48 year old female presented with angina and exertional shortness of breath. She had a normal cardiovascular examination, negative cardiac enzymes and an unremarkable chest X-ray. She did, however, have T-wave inversions in leads V1-V3. Transthoracic echocardiography (TTE), as the first imaging investigation, led to an initial provisional diagnosis of a coronary-cameral fistula. It showed unusual colour Doppler signals in the right ventricle and a prominent pattern of diastolic flow within the right ventricular myocardium, especially along the interventricular septum. A subsequent multimodality approach, correlating images from angiography, CT and MRI was instrumental in confirming the diagnosis of ARCAPA and planning for surgical correction. Cardiac CT and MRI are non-invasive, three-dimensional imaging modalities with high diagnostic accuracy for coronary artery anatomic anomalies. If echocardiography and conventional angiography have been inconclusive, cardiac CT and MRI are especially important diagnostic tools.

Modified Bentall technique for aortic root replacement: a simplified approach to the short left coronary artery.

The short left coronary artery encountered during aortic root replacement with the modified Bentall (coronary button) technique may pose a significant problem for the surgeon. A simple solution entails the placement of a short interposition Dacron graft between the native coronary artery and the aortic graft. This approach has been successfully employed in 2 patients.

Aortic valve replacement with stentless porcine bioprostheses.

Aortic valve replacement with stentless porcine valve should provide superior hemodynamic results to stented porcine valve because the obstruction caused by the stent and the sewing ring is eliminated. In addition, the coronary sinuses of the recipient may allow for better dissipation of the mechanical stress to which the leaflets are subjected during diastole, thus enhancing durability of the heterograft. Aortic valve replacement with stentless glutaraldehyde-fixed aortic porcine bioprosthesis was carried out successfully in six young sheep. These animals were hemodynamically evaluated at 3 to 6 months after operation and found to have no resting gradients or any degree of aortic regurgitation. Explantation of the aortic heterograft revealed that it was well healed in the aortic root and had no evidence of any calcification. A clinical trial has been initiated and the results in the first five humans who underwent aortic valve replacement with a stentless porcine aortic bioprosthesis have been satisfactory.

Frequency content and sex difference of the Frank lead signal-averaged ECG in a population with significant coronary artery disease. Comparison with concurrent 12-lead ECG morphology.

The 12-lead electrocardiogram (ECG) and a 100-beat signal-averaged Frank lead ECG (SAECG) at a sampling rate of 1,000 Hz and with 16-bit resolution were recorded from 52 women and 256 men with significant coronary artery disease presenting for coronary artery revascularization. The QRS portion of each Frank lead was digitally filtered in four bandwidths: 0-10, 10-60, 60-150, and 150-250 Hz. The root-mean-square (RMS) voltage of each filtered signal was calculated as an absolute value and normalized as a percentage of the sum of the four filters, creating 27 variables. Three groups were formed using the presenting 12-lead ECG: N-ECG, ST-ECG, and MI-ECG. Despite variation in 12-lead morphology, concordance was dominant in the RMS values of the SAECG in sex comparisons within and between groups. There was significant sex difference of the RMS values in 6 of the 15 absolute RMS variables within the three groups. Women had no significant between-group difference, and men had a significant between-group differences in five absolute values and one normalized RMS value. P was considered significant at < .05.

Ascending aorta to bifemoral bypass--a ventral aorta.

In the decade since April 1975 we accumulated a series of 18 patients with arterial conduits from the ascending aorta to the femoral arteries, 10 men aged 53 to 75 years (mean, 60 years) and eight women aged 33 to 56 years (mean, 50 years). In the first two patients, the conduit was placed subcutaneously; in the remaining 16 patients, it was placed behind the rectus muscle and in front of the posterior rectus fascia, thus following the ventral anastomotic axis of the internal mammary and inferior epigastric arteries. The conduit is not visible, palpable, or compressible in this position. This approach was usually chosen because of multiple failures of standard intra-abdominal and axillofemoral vascular reconstructions. Five patients had concurrent intramediastinal procedures, mostly coronary bypass or innominate artery repair. The early operations were performed with Dacron grafts with a bifurcation constructed just below the umbilicus. In the last nine patients, we have used an 8 or 10 mm polytetrafluoroethylene (PTFE) prosthesis and connected it to a 6 or 8 mm PTFE crossfemoral bypass. No operative deaths occurred. The 5-year patency rate by life-table analysis is 70%. This operation is an alternative to axillofemoral bypass in patients with an inoperable abdominal aortic aneurysm.

Intermittent percutaneous infusion into the hepatic artery of cytotoxic drugs for hepatic tumours.

Between June 1, 1976 and Apr. 30, 1981, 157 patients were treated for inoperable cancer of the liver by intermittent percutaneous infusion of chemotherapeutic agents into the hepatic artery. The majority of these patients had metastatic colorectal cancer. The regimen of chemotherapeutic infusion evolved during the study and is described. The survival of the total group of patients is analysed according to type of cancer, extent of disease, dosage and combination of drugs. This therapeutic modality appears to benefit patients with metastases from colorectal cancer confined to the liver. The complication rate for this procedure is relatively low. The results from this study suggest that intermittent percutaneous infusion of cytotoxic agents into the hepatic artery is worthwhile for selected patients and should be studied further in combination with other forms of therapy.