Cardiac Troponin T to evaluate myocardial protection via intermittent cold blood or continuous warm blood cardioplegia in coronary artery bypass grafting

BACKGROUND

The aim of our study was to evaluate the efficacy of myocardial protection during coronary artery bypass grafting (CABG) in cold blood intermittent (CBIC) and warm continuous blood cardioplegia (WCBC). To assess myocardial necrosis, Troponin T, a structural protein belonging to the troponin complex, was measured. Troponin T is released in the blood stream 4 hours after myocardial damage, and it does not cross-react with the isomeric form of the skeletal muscle.

METHODS

Our study involved 20 consecutive patients, scheduled for isolated CABG. They were divided into two groups: the first group (10 patients; 8 m, 2 f) underwent surgery with the use of CBIC, the second group (10 patients; 9 m, 1 f) with WCBC. The serum levels of cardiac Troponin T (cTn-T) were all <0.2 microg/l before operation.

RESULTS

In the CBIC the mean cTn-T peaked on the 1st day after CABG, in the WCBC group the first peak occurred in the 2nd hour after arrival in the intensive care unit, and the second peak occurred on the 4th day postoperatively. The mean serum cTn-T was lower in the WCBC vs CBIC group from the 1st to the 5th day postoperatively, with a statistical difference on the 1st day (p<0.05). In the CBIC group either the cTn-T peak values (r=0.77; p<0.02) or area under the concentration curve of cTn-T release (r=0.85; p<0.004), were directly correlated with the aortic cross-clamping time. This was not demonstrated in the WCBC. CPK and CK-MB peaked in both groups 6 hours after arrival in the intensive care unit and on the 1st day postoperatively, with higher values at 6 hours in the WCBC group (p<0.05). The CK-MB/CPK ratio was significantly lower in the WCBC group at the six hours (p<0.05).

CONCLUSIONS

The results of this preliminary study suggest that fewer necrosis markers are released during CABG in the WCBC group; in the CBIC group the release of cTn-T whether measured by peak serum level or by area under the curve, shows a statistically significant correlation with cross-clamping time. Warm blood cardioplegia is safe and supplies adequate myocardial protection during CABG; the more prolonged cross-clamping is, the more myocardial protection is afforded by WCBC.

Electrode positioning for reliable telemetry ECG recordings during social stress in unrestrained rats

We describe a surgical procedure for optimizing the location of telemetry ECG leads in rats. The new location was aimed at obtaining an accurate representation of ECG features throughout the cardiac cycle by limiting the voltage instability usually observed during intense somatomotor activity and improving the signal-to-noise ratio. The two electrodes (wire loops) were fixed on the dorsal surface of the xiphoid process and in the anterior mediastinum close to the right atrium. The implantation procedure was fast, little invasive, and allowed animals to completely recover from intervention. The performance of the "improved" location (IL, n = 10) with respect to two subcutaneous (SC) positionings ("conventional positioning" CSP, n = 5; "updated location," USL, n = 5) was evaluated by comparing ECGs obtained in baseline, stress and recovery conditions and during different behavioral activities (immobility and grooming). The resident-intruder test (emotional/physical challenge) was chosen as experimental stress paradigm. The noise level of ECGs obtained from IL rats was lower than in CSP and USL animals, in all recording conditions. Percentages of correctly recognized beats (CRBs) over the total number of beats (TBs) were significantly higher in IL rats than in CSP and USL animals, both in baseline conditions (99% vs. 11% and 40%) and situations involving high somatomotor activity (stress: 97%, 5% and 16% recovery; 97%, 7% and 15%) (p < 0.01). The performance of IL as compared to CSP and USL was also better when percentages during grooming and immobility were considered (grooming: 93% vs. 4% and 23%: immobility: 97%, 6%, and 33%; p < 0.01).

Late spontaneous chylopericardium following complex cardiac surgery

Chylopericardium as an isolated complication after open heart surgery is a rare event. We present here a case of late postoperative chylopericardium and comment on the clinical course, the aetiopathology and treatment.

Migrant sensory neuritis associated with AIDS: case report

We studied an AIDS patient who suffered from numbness, paresthesias and pain in the territories of different non-contiguous cutaneous nerves at different times. A transitory partial loss of touch and pinprick sensibility was also present in the same cutaneous areas. Sensory conduction velocities and SAP amplitudes were normal. The clinical picture was consistent with the Migrant Sensory Neuritis of Wartenberg. This rare neuropathy has never previously been described in patients affected by AIDS.

Unusual synkinetic movements between facial muscles and respiration in hemifacial spasm

We describe two cases of hemifacial spasm (HFS) with unusual synkinetic movements between facial muscles and respiratory activity. Patient 1 developed an idiopathic HFS. She underwent microvascular decompression surgery, followed by transitory facial nerve palsy; she recovered but later developed a facial synkinesia characterized by involuntary and forced eyelid closure on spontaneous and deep breathing; the orbicularis oculi muscle was active also when her mouth was open (the so-called Marin-Amat syndrome). Patient 2, 1 year after a peripheral facial nerve palsy (Bell's palsy), developed an HFS together with synkinetic movements between the orbicularis oculi muscle and respiration. In both cases electrophysiological studies showed pathological synkinetic electromyographic activity. An enhanced hyperexcitability of brain stem interneurons and facial motoneurons could be suggested to explain the phenomenon.

On the cause of tendon areflexia in the Holmes-Adie syndrome

A case of Holmes-Adie syndrome was studied clinically and electrophysiologically. A total loss of tendon reflexes was observed in upper and lower limbs. The main electrophysiological finding was a marked increase of the central conduction time after stimulation of peroneal and tibial nerves. Motor evoked potentials in soleus muscle after transcranial magnetic stimulation showed normal threshold and latencies. We suggest that tendon areflexia could be a consequence of a dysfunction of somatosensory large diameter afferent fibres at the spinal level.

Acute sensory and autonomic neuropathy: possible association with coxsackie B virus infection

This report describes a 26 year old woman with a Coxsackie B virus infection complicated by an acute pandysautonomic and sensory neuropathy. Electrophysiological studies suggested an axonal neuropathy. A sural nerve biopsy performed early in the disease showed axonal degeneration with a virtual absence of unmyelinated fibres and moderate loss of myelinated fibres, mainly affecting the small fibres; this differs from previous reports. An immune-mediated or direct virus action might explain the pathogenesis of this unusual evolution of a viral infection.

Magnetic motor evoked potentials (MEPs) in masseter muscles

Electromyographic responses of the masseter muscles and orbicularis oris muscles following transcranial magnetic stimulations were recorded with surface and needle electrodes. MEPs in masseter muscles (latency 6.9 +/- 0.71 ms, mean +/- SD) due to activation of controlateral cortico-nuclear connections were evoked by magnetic stimulations at 4 cm laterally to the vertex on the biauricular line. These MEPs were followed bilaterally by a silent period lasting about 20 ms and, less constantly, by a later silent period lasting up to 80 ms. The ipsilateral responses to the same stimuli presented shorter latencies and higher amplitudes and they were ascribed to direct stimulation of the trigeminal nerve, probably its intracisternal portion. Ipsilateral masseter "cortical" MEPs could be elicited only by a lower output setting (70% of the maximum output) of the stimulator. Orbicularis oris MEPs were polyphasic and dispersed with latencies ranging from 7 to 11 ms. In patients with hemispheric or capsular ischemic lesions "cortical" MEPs were absent when stimulating the affected hemisphere and present when stimulating the unaffected one. We suggest that the direct corticomotoneuronal projections for the masseter are mainly crossed.

[Intraoperative angioplasty and bypass for the treatment of diffuse symptomatic coronary lesions]

After a brief description of the intraoperative angioplasty technique carried out together with direct revascularization through bypass with venous segments or with internal mammary (IMA) we hereby report the immediate and mid-term results obtained in 18 patients with this treatment. The simplicity of execution, having the possibility to operate on still heart and under the direct vision of the lesion the rareness of any complication, the fact that the coronary segment is open also during all checks done after 3 years from the treatment, and finally the considerable improvement in clinical symptomatology, lead the authors to consider this therapeutical succession possible in some selected cases, for which surgical operation is necessary.

Cell metabolism response to cardiopulmonary bypass in patients undergoing aorto-coronary grafting

The main parameters of muscle acid-base, water and energy metabolism were studied in ten patients undergoing low-flux (1.5 l/min/m2), low-pressure (40 to 60 mmHg) hypothermic (26 degrees C) cardiopulmonary bypass (CPB) for aortocoronary grafting; absolute gas exchange and haemodynamic data were also measured throughout the entire CPB period. At the end of CPB a substantial preservation of water and energy metabolic indexes was found; a condition of extracellular metabolic acidosis was apparently sustained by muscle cell anaerobic glycolysis enhancement with a consequent increase of both muscle and plasma lactate content. Subnormal cell phosphocreatine levels as well as reduced bicarbonate buffer stores and decreased intracellular pH, were detected. Direct limiting effects of hypothermia on tissue O2 delivery and muscle oxidative metabolism as well as vasoconstriction and arteriovenous shunting associated with CPB procedures are likely to be involved in the above mentioned alterations of cell metabolism.

Surgical treatment of left main coronary stenosis. Notes on 179 consecutive patients

The authors report the clinical haemodynamic and angiographic data and early and late postoperative results of 179 patients consecutively operated on for left main coronary artery stenosis. Operative mortality was 3.9%; incremental risk factors were identified by univariate analysis and included female sex, unstable angina pectoris and congestive heart failure. Late postoperative mortality was 4.9%. After a mean follow-up of 31 months overall survival is 91.6%; the great majority of survivors are doing well, free from anginal pain, while 16.4% of patients experience recurrent angina pectoris of lesser severity than before operation (I-II C.C.S. class) and well controlled by medical treatment alone.

Effects of low flux-low pressure cardiopulmonary bypass on intracellular acid-base and water metabolism

In eight patients undergoing open heart surgery for elective myocardial revascularization, extra-intracellular acid-base and water metabolism parameters were studied before and after cardiopulmonary bypass procedures. All patients presented a different degree of metabolic acidosis related to plasma lactate increase. Intracellular acid-base indexes did not change significantly, though all but one patient showed an intracellular buffers consumption. Both total muscle and extracellular water increased, while intracellular water did not change. It was concluded that low flux-low pressure perfusion CPB was related to a substantial preservation of cell integrity.

Cardiopulmonary bypass: a low T4 and T3 syndrome with blunted thyrotropin (TSH) response to thyrotropin-releasing hormone (TRH)

Thyroid hormone serum concentrations, the thyrotropin (TSH) and prolactin (PRL) response to thyrotropin-releasing hormone (TRH) were evaluated in patients undergoing cardiopulmonary bypass (CPB) conducted in hypothermia. During CPB a marked decrease of thyroxine (T4) and triiodothyronine (T3) concentration with a concomitant increase of reverse T3 (rT3) were observed similarly to other clinical states associated with the 'low T3 syndrome'. Furthermore, in the present study elevated FT4 and FT3 concentrations were observed. In a group of patients, TRH administered during CPB at 26 degrees C elicited a markedly blunted TSH response. In these patients, PRL concentration was elevated but did not significantly increase after TRH. The increased concentrations of FT4 and FT3 were probably due to the large doses of heparin administered to these patients. Thus, the blunted response of TSH to TRH might be the consequence of the elevation of FT4 and FT3 in serum, however, other factors might play a role since also the PRL response to TRH was blocked.

Effect of mifentidine on histamine-stimulated human atrium "in vitro": comparison with ranitidine and cimetidine

The new H2-antagonist mifentidine was tested on human atrium, in comparison with cimetidine and ranitidine, for its activity against histamine-induced inotropic effect. Mifentidine was found to be 10 times more potent than ranitidine and 100 times more potent than cimetidine. The kinetics of the three compounds are typical of a competitive antagonism and the pA2 value was of 8.60, 6.35, 5.94 for mifentidine, ranitidine and cimetidine, respectively. Our data confirm previous findings in another isolated heart preparation, namely the guinea-pig papillary muscle.

Sonographic findings in cephalothoracopagus-conjoined twins

Antepartum diagnosis of syncephalus thoracopagus-conjoined twins was made at the 27th week of gestation. The authors stress the need for early recognition of this fetal malformation.

Negative inotropic effect of some H2-receptor antagonists on the isolated human atria

H2-Receptor antagonists were found to possess in various degrees a negative inotropic effect on human atria in vitro. This effect seemed to be independent of H2-receptor blockade and, at least in the case of oxmetidine, seemed to involve calcium ion transport and/or utilization.

[Echotomography in polycystic renal disease]

Sonography is a safe and suitable diagnostic tool; to date it appears to be the most valuable method for detecting renal cystic lesions. In particular ultrasound examination, if a wider district is screened, can demonstrate the coexistence of the cystic disease in different organs. The Authors report a case of renal polycyctic disease in which the sonographic examination was extended to the entire abdomen disclosing simultaneous involvement of the kidneys and the liver.

Aortoplasty with the left subclavian flap in older children

Ten patients between 8 months and 9 years of age (average 4.3 years) underwent surgical relief of coarctation of the aorta by the technique of left subclavian flap aortoplasty. Before operation, nine patients had systolic hypertension in the upper extremity (average 145 mm Hg) and all had a significant pressure gradient across the coarctated aortic segment (average 45 mm Hg). The hospital and late mortality were zero. The follow-up over 7 years has shown complete relief of the coarctation and no ischemic impairment or functional limitation of the left upper extremity. The blood pressure returned to normal in all patients. Hemodynamic and angiographic studies, performed in one case, demonstrated adequate growth of the repaired segment and absence of a pressure gradient across the previously narrowed area. The time interval between the peak of the femoral pulse and the dicrotic notch of the carotid pulse, recorded postoperatively, was normal. We consider the left subclavian flap technique to be the operation of choice in infancy and also in older children, whenever the anatomic configuration of the coarctation suggests that subsequent growth would be severely restricted if other techniques were used.

Indirect arterial pulse tracings in children with coarctation of the aorta before and after operation

Eleven children with coarctation of the aorta were investigated before and after surgical treatment, using simultaneous indirect carotid and femoral pulse wave tracing. The timing of the onset of the femoral pulse in the children with coarctation, both before and after operation, did not differ significantly from normal. However, the time interval between the peak of the femoral pulse and the dicrotic notch of the carotid pulse was significantly shorter than normal in the children with coarctation before operation. After operation, the peak femoral to carotid dicrotic notch time interval was restored to normal. It is suggested that this simple non-invasive test might be of value in the long-term follow-up of patients after operation for coarctation of the aorta, particularly in those undergoing operation early in childhood, to detect residual or recurrent coarctation.

[Treatment of inflammatory complications of permanent implanted pacemakers]

The Authors report an experience of 165 patients who underwent to implantation of artificial pacemaker from January 1973 to December 1974 and report 16 cases of infection. They consider many surgical and biologic factors that can have caused uprinsing of infection. The Authors report the therapeutic treatment the patients underwent and conclude that the best treatment is the implantation, to another seat, of new pacemaker.