Quantification of microvascular resistance in patients with diabetes mellitus [abstract]

Near Infrared Photoplethysmography (NIRP) is a non-invasive technique that has the potential to be used to assess the state of the peripheral nerves and microcirculation. However, the parameters that reflect the state of the microvascular system have not been established. Therefore, we tested the hypothesis that the resistance of the blood vessels in the microcirculation can be determined by analyzing the temporal components of the photoplethysmographic trace. NIRP incorporates two light-emitting diodes and a photodetector. The emergent light enters the skin and penetrates to the level of the dermis, is backscattered, collected by the photodetector and converted to a recordable trace. This trace consists of a series of pulses synchronous with the heart period, Th. It is possible to divide each pulse into a rise time from baseline to peak, Tg, and fall time from peak to baseline, Ta. All NIRP recordings were taken from the right index finger with the person in the supine position. In a first study involving five healthy male volunteers, the subjects right arm was cuffed approximately three minutes during which he exercised the fingers to increase a buildup of tissue metabolites; this was done in order to decrease microvascular resistance. In a second study, the above parameters (Th, Tg and Ta) were measured in 31 patients with chronic diabetes mellitus (diabetic group, DG) and compared to those of 29 healthy normal persons (healthy group, HG). In the first study, the ratio of the rise time to the heart period (Tg/Th) or of the rise time of the fall time (Tg/Ta) was increased, whereas that to the fall time of the heart period (Ta/Th) was decreased. In the second study, the mean for the Tg/Th was 0.235 ñ 0.008 (mean ñ sem) for the HG and 0.292 ñ 0.007 for the DG; the increase was highly significant, p< 0.001 (one-tail unpaired t-test). The mean for the Tg/Ta was 0.312 ñ 0.013 for the HG and 0.413 ñ 0.012 for the DG; this increase was also highly significant, p< 0.001. The mean for the Ta/Th was 0.765 ñ 0.008 for the HG and 0.711 ñ 0.006 for the DG; the decrease was highly significant, p< 0.001. In conclusion, an increase in microvascular resistance was reflected in an increase in the rise time and a decrease in the fall time. Thus this system appears to be a useful one in quantifying the increase in microvascvular resistance in diabetics. (AU)

Quantification of EEG waves in healthy persons and patients with brain disorders [abstract]

The biological processes that give rise to many disorders of the brain such as schizophrenia, depression and epilepsy are yet to be clearly explained. The electroencephalograms (EEG) from patients with these disorders have been reported to exhibit "chaotic" properties. Coarse-grained correlation dimension (Dcg) has been found to be an effective tool in analyzing waveforms with chaotic properties. We therefore tested the hypothesis that the Dcg of the EEG of patients with the above disorders will be different from those of healthy volunteers. Twenty-five minutes of EEG recordings were obtained from different regions of the brain of 20 healthy volunteers, seven patients with schizophrenia, one with depression, and one with partial seizure. Each person's EEG was edited to obtain 51 seconds of artifact-free recording. A software was developed in-house and used to obtain estimates of the Dcg. A confidence interval for each of the 21 EEG electrode points was established for the healthy volunteers (control group). Compared to the control group, the Dcg measurements of some of the schizophrenics, of the depressed patients, and that of the epileptics showed significant differences (p< 0.005). The results of this study indicate that the Dcg of the EEG for some brain disorders may be of use in the diagnosis of these conditions. Given the preliminary nature of this study, further work with larger sample sizes will be necessary in order to determine the reliability and sensitivity of this method. (AU)

Coronary artery bypass graft outcome: the Trinidad and Tobago experience

The study is a retrospective review of the demographic, clinical, angiographic, and operative data of the first 205 consecutive CABG operations performed by Caribbean Heart Care at the Eric Williams Medical Sciences Complex (EWMSC), Trinidad and Tobago, between November 1993 and December 1997. The aim of the study was to determine the in hospital and intermediate term follow up results. The mean age of patients was 59 ñ 10 years and 78 percent male. Sixty-four percent were of East Indian descent, whereas, 16 percnt were of Africian descent. Forty-eight percent of the patients were hypertensive, 46 percent were diabetic, 33 percent had hyperlipidaemia, 20 percent had a recent history of cigarette smoking and 16 percent were obese. Sixty-five percent had a positive family history of ischaemic heart disease. The average time interval between angiography and surgery was 2.3 months. At the time of angiography, 63.5 percent of patients had Canadian Cardiac Society (CCS) class 3 or 4 angina. The mean ejection fraction was 61 ñ 15 percent. Wall motion abnormalities were seen in 67 pecent of patients. Significant stenoses of the left anterior descending artery, right circumflex artery, circumflex and ramus coronary arteries were present in 91 percent, 78 percent, 54 percent and 5 percent, respectively. Many patients (67 percent) had severe diffuse disease on angiography. The mean intensive care stay was 2.2 ñ 0.8 days. In hospital mortality was 3.9 percent (8/205). THe most frequent post operative complicaton was haemorrhage (2.6 percent). Acute renal failure occurred in 2.1 percent; pulmonary collapse, 1.6 percent; 1 percent and cardiac arrest , 1 percent. Both sternal wound infections and systemic sepsis occurred in 0.5 percent. Intermediate term follow-up data were obtained for 92 percent (189/205). The duration of follow-up ranged from 1 to 5 years (mean 3.7 years). During the follow up period, 7 patients (3.4 percent) died. Angina severity was reduced from a mean CCS score of 2.61 ñ 0.95 before CABG ot 1.22 ñ 0.55 at the time of follow up (p<0.0001). Overall 4-year mortality compared favourably with data from international studies. Among survivors, quality of life improved as evidenced by the reduction in the mean angina score.(Au)

Coronary artery bypass graft outcome: the Trinidad and Tobago experience

The study is retrospective review of the demographic, clinical, angiographic, and operative data of the first 205 consecutive CABG operations performed by Caribbean Heart Care at the Eric Williams Medical Sciences Complex (EWMSC), Trinidad and Tobago, between November 1993 and December 1997. The aim of the study was to determine the in-hospital and intermediate-term follow-up results. The mean age of patients was 59 +/- 10 years and 78 were male. Sixty-four per cent were of East Indian descent, whereas 16 were of African descent. Forty-eight per cent of the patients were hypertensive, 46 were diabetic, 33 had hyperlipidaemia, 20 had a recent history of cigarette smoking and 16 were obese. Sixty-five per cent had a positive family history of ischaemic heart disease. The average time interval between angiography and surgery was 2.3 months. At the time of angiography, 63.5 of patients had Canadian Cardiac Society (CCS) class 3 or 4 angina. The mean ejection fraction was 61 +/- 15. Wall motion abnormalities were seen in 67 of patients. Significant stenoses of the left anterior descending artery, right circumflex artery, circumflex and ramus coronary arteries were present in 91, 78, 54 and 5, respectively. Many patients (67) had severe diffuse disease on angiography. The mean intensive care stay was 2.2 +/- 0.8 days. In-hospital mortality was 3.9 (8/205). The most frequent post-operative complication was haemorrhage (2.6). Acute renal failure occurred in 2.1; pulmonary collapse, 1.6; stroke, 1 and cardiac arrest, 1. Both sternal wound infections and systemic sepsis occurred in 0.5. Intermediate-term follow-up data were obtained for 92 (189/205). The duration of follow-up ranged from 1 to 5 years (mean 3.7 years). During the follow-up period, 7 patients (3.4) died. Angina severity was reduced from a mean CCS score of 2.61 +/- 0.95 before CABG to 1.22 +/- 0.55 at the time of follow-up (p < 0.0001). Overall 4-year mortality compared favourably with data from international studies. Among survivors, quality of life improved as evidenced by the reduction in the mean angina score.

Coronary artery bypass surgery in Trinidad: morbidity and mortality - Poster abstract

OBJECTIVE: To determine whether Coronary artery bypass grafting (CABG) in Trinidad influenced morbidity and mortality. METHOD: Retrospective review of the demographic, clinical and angiographic data of the first 205 consecutive CABG operations performed by Caribbean Heart Care at the Eric Williams Medical Sciences Complex, Trinidad, between November 1993 and December 1997. RESULTS: The mean age was 59 ñ 10 years and 74 percent were males. The average time interval between angiography and surgery was 2.3 months. At the time of angiography, 69 percent of patients had class 3 or 4 angina (CCS). The mean ejection fraction was 63 ñ 13 percent. Many patients (64 percent) had severe diffuse disease on angiography. The in-hospital mortality was 8/205 (3.9 percent). Follow-up data were obtained for 189/205 (92 percent). The duration of follow-up ranged from 1 to 5 years. During the follow-up period, 7/189 patients. (3.4 percent) died. Angina severity before and after surgery was determined in 174 surviving patients. Angina severity was reduced from a mean CCS score of 2.61 ñ 0.95 before CABG to 1.22 ñ 0.55 after CABG (p<0.0001). CONCLUSION: Overal 4-year mortality compared favourably with data from international studies. Amongst survivors, quality of life improved as evidenced by the reduction in the mean angina score.(AU)

Coronary artery bypass graft outcome: the Trinidad and Tobago experience.

The study is retrospective review of the demographic, clinical, angiographic, and operative data of the first 205 consecutive CABG operations performed by Caribbean Heart Care at the Eric Williams Medical Sciences Complex (EWMSC), Trinidad and Tobago, between November 1993 and December 1997. The aim of the study was to determine the in-hospital and intermediate-term follow-up results. The mean age of patients was 59 +/- 10 years and 78% were male. Sixty-four per cent were of East Indian descent, whereas 16% were of African descent. Forty-eight per cent of the patients were hypertensive, 46% were diabetic, 33% had hyperlipidaemia, 20% had a recent history of cigarette smoking and 16% were obese. Sixty-five per cent had a positive family history of ischaemic heart disease. The average time interval between angiography and surgery was 2.3 months. At the time of angiography, 63.5% of patients had Canadian Cardiac Society (CCS) class 3 or 4 angina. The mean ejection fraction was 61 +/- 15%. Wall motion abnormalities were seen in 67% of patients. Significant stenoses of the left anterior descending artery, right circumflex artery, circumflex and ramus coronary arteries were present in 91%, 78%, 54% and 5%, respectively. Many patients (67%) had severe diffuse disease on angiography. The mean intensive care stay was 2.2 +/- 0.8 days. In-hospital mortality was 3.9% (8/205). The most frequent post-operative complication was haemorrhage (2.6%). Acute renal failure occurred in 2.1%; pulmonary collapse, 1.6%; stroke, 1% and cardiac arrest, 1%. Both sternal wound infections and systemic sepsis occurred in 0.5%. Intermediate-term follow-up data were obtained for 92% (189/205). The duration of follow-up ranged from 1 to 5 years (mean 3.7 years). During the follow-up period, 7 patients (3.4%) died. Angina severity was reduced from a mean CCS score of 2.61 +/- 0.95 before CABG to 1.22 +/- 0.55 at the time of follow-up (p < 0.0001). Overall 4-year mortality compared favourably with data from international studies. Among survivors, quality of life improved as evidenced by the reduction in the mean angina score.