Cuban Medical Research
Gender and Ischemic Heart Disease

Authors: Dr. Caridad M. Castañeda Gueimonde (1), Dr. Reynaldo Amigo González (2), Dr. Ada Prior García (3)

ABSTRACT: A prospective longitudinal study was conducted in patients with precordial pain between 1990 and 2000 in the Provincial Ergometrics Service in Matanzas, to evaluate the effectiveness of the Diagnostic Ergometric Test in patients of both sexes. The random sample included 1400 patients who met the pre-established inclusion, exclusion and exit criteria. The independent variables were matched with the dependent variable in contingency tables, the risk by crossed products and the Reliability Intervals for 95% were calculated. The Chi square summary of Mantel-Haenszel for significant statistical association was also calculated.

The main finding was more positive cases using the Diagnostic Ergonometric Test (DET) in females in all age groups, regardless of their association with the studied cardiovascular risk factors, the accompanying symptoms, occupation or pain during the test. Exercise echocardiography should thus be included for certain diagnosis of ischemic heart disease in women, to reduce the possibility of false positive results due to women’s physiological makeup.

Introduction

Western women’s life expectancy is eight years higher than that of men. Overmortality in men is, in 40% of cases, due to ischemic heart disease. It has been demonstrated that the diagnosis of heart disease in women is difficult (1, 2, 3), when methods such as the ergometric test are used. These opinions are based on the following criteria:

1. More catecholamine is released during physical exertion in women than in men. This explains the higher percentage of myocardial ischemia in healthy coronaries in women, which causes an increase in muscular tone and vessel spasms.

2. Repolarization disorders are found in basal electrocardiography, which could be secondary to variations in estrogen levels, because the chemical structure of these hormones is very similar to that of the digitalic components that are known to alter the ST segment considerably, during both in repose and during exertion.

3. In addition, high prevalence of thoracic pain, from the prolapse of the mitral valve, neurocirculatory asthenia, and other pathologies that raise lung vascular resistance, and which are more frequent in women, can result in false positives.

Cuban women are presently 37.6 % of the labor force in the country. They carry extra burdens in family, society and the workplace, and often do not insist on the rights they have. Thus, it is necessary to review some physiological aspects that may help clarify their health problems and allow them to achieve greater stability in their work, social and family lives. The need arises for methods of, which in the province of Matanzas causes 1.8 deaths in women for every male death.

Objectives

General Objective:

Analyze the positive results of Diagnostic Ergometric Tests in terms of gender in patients who sought assistance in the Provincial Ergometry Service in Matanzas between 1990 and 2000.

Specific Objectives:

Compare positive results of Diagnostic Ergometric Tests by sex and age groups.
Explore the concomitant association of risk factors in correspondence with positive results of the Diagnostic Ergometric Tests by sex.
Correlate the above-mentioned clinical symptoms, occupation and alterations during the test with positive results of Diagnostic Ergometric Tests and sex.

Material and Method

A prospective observational longitudinal study was carried out from January 1990 to December 2000 on patients with precordial symptoms who visited the Jose Ramon Lopez Tabranes and Faustino Perez Hospitals in Matanzas City for diagnostic ergometric testing.

1400 patients who were tested in the specified time period were included, following a systematic probalistic sampling. A random selection was made of one number between 1 and 10 from the list of patients on a given day. One out of every four patients meeting the previously established inclusion, exclusion and exit criteria were chosen. Universe and sample are the same in the design of this model.

Selection Criteria

All patients visiting the chosen service with antecedents of precordial pain from January 1^st, 1990 to December 31^st, 2000, without previous diagnosis of ischemic heart disease.

Exclusion Criteria

Personal pathological antecedent of ischemic heart disease (heart attack or chest angina).

Exit Criteria

1. Uncertain results of Diagnostic Ergometric Tests for not reaching sub-maximum heart rate.

2. Interrupted test for lack of cooperation.

Methodology

The following variables were included in the study:

Dependent Variable:

Positive Ergometric Tests

Independent Variables

1. Sex

2. Personal pathological antecedent of high blood pressure

3. Personal pathological antecedent of diabetes mellitus

4. Smoking habit

5. Overweight and obesity

Information Gathering

Data was elicited from interviews conducted by specialists carrying out the testing, and the data obtained was entered on a form prepared by the Ergometry Service (Appendix 1). The data was then entered into a specially designed computerized data base, and sent to SPSS 10 for statistical analysis.

Analysis

Data on independent variables was matched with that of the dependent variable in a risk approach on contingency tables. For each of these, the Crossed Product Rate was calculated, as well as the reliability intervals for 95 %.

The Martel-Haenszel Chi square summary (equivalent to a corrected McNemar Chi Square summary) was used to find significant statistical association. Statistical association was considered significant when the value of p was less than 0.05 and the reliability interval of 95% did not include value 1.

Those independent variables which did not include value 1 in their 95% reliability intervals and whose p values were lower than 0.05 were identified as risk factors.

The results were presented in statistical tables and graphs using Microsoft Word/97 and Microsoft Excel/97.

Discussion of Results

Of the total number of Diagnostic Ergometric Tests (1400), 597 were conducted on women, and 803 on men. The analysis of the relationship between sex and positive Diagnostic Ergometric Test results shows that 32.07 % of the tests were positive: 222 women (49.94 %) and 227 men (50.56 %). It can be observed that positive results in women were higher (37.1 %) than in men (28.2 %). This can be attributed to such factors as false positives related to the variations that influence positive results in the test: menstrual periods, during which estrogen levels are lowest, and the pre-ovulating period in which these levels are highest. This aspect of women’s physiology and positivity in the test cause a variation of the ST for the effort electrocardiogram. Some factors affecting women’s sensitivity in the test are:

Low hematocrit
Low levels of myocardial intracellular potassium
Alteration of myocardial distensibility (1,2,3)

The average age in the sample was 44.74 (+ 9.38) years, with the highest frequency in the 40 – 49 group for both men and women, 42.34 % and 37.44 % respectively. The highest percentage of positive tests however, was found in women in the 60 – 69 group (66.7 %), and in men in the older-than-70 group (50 %). The percentage was higher in women for all the age groups (except for extreme ages). These results draw our attention since ischemic heart disease is greater in men then in women by 10:1, up to 45 years of age. Between 45 and 55 years it is 4:1, and from 55 years forward, it is 1:1. We thus assume that these results may be biased by false positives (1, 2, 5). (See Figure 1)

Figure 1

The Framingham study shows that intervention measures on risk factors can modify mortality due to ischemic heart disease up to 60 %. (2, 4, 6). As for the selected cardiovascular risk factors, they were present in 71.79 % of the patients in the sample, and in 76.6 % of the positive cases. A 34.23 % positivity rate was present in patients with these risks, in contrast with a 26.5 % in those patients presenting none of these factors.

The most frequent risk factor was high blood pressure among women (OR=1.482[1.062;2.069] p=0.013), and smoking in men (OR=1.397[1.027;1.901] p=0.020) with 55.4 % and 53.3 %, respectively. (7)

The positivity index was higher in women with one, two or no risk factors (35.6 %, 44.9 % and 33.7 % respectively). It is only slightly higher in men with 3 or 4 factors. (See Figure 2)

Figure 2

The predominant type of pain in the population under stuy was atypical pain with a 66.29% rate, but when pain was related to positive results in the test, we found that typical precordial pain was the one most frequent for both men and women, with a slight predominance in men. Women, however, showed a higher positivity rate (81.7 % to 73.9%). Positive results were high for this group, with a rate of 77.54%, which confirms the importance of an adequate anamnesis.

The presence of other symptoms, such as dyspnea and palpitations in 50% of the sample cases with positive results, show a positivity rate of 34.98 %. In the analysis by sex, dyspnea was more frequent in men with a positive Diagnostic Ergometric Test (82.4%), while palpitations were present in 46.4% of women with positive Diagnostic Ergometric Tests. The positivity rate for both symptoms was higher in women; either when they appeared in concomitant association or not (8) (See Figure 3)

Figure 3

The occupation variable shows that 79.5 % of the patients in the sample are workers, and so are 76.1 % of those testing positive. The highest positivity rate is found among retired patients. The next highest rate of positive tests is found in both sexes in the group of working patients (women: 62.2 %, men 89.9 %), while the highest positivity rate for both sexes is found among retired patients with a slight female predominance (45 % to 43.2 %) (See Figure 4)

Figure 4

The alterations that occurred during the Diagnostic Ergometric Test (High Blood Pressure Reaction, arrhythmias, and precordial pain) were found in 54.36% of the individuals in the sample, with High Blood Pressure in 52.12% of the positive cases. The presence of alterations during the procedure determined a positivity rate of 38.37%. Following a risk approach, a significant association was observed for High Blood Pressure in women (OR=1.660[1.186;2.322]p=0.002), and arrhythmia in men (OR=2.355[1.475;3.758]p=0.000).

100% of the men who suffered from precordial pain, or arrhythmia with precordial pain, or the three alterations in association, all showed positive results in the test; while women with precordial pain only, or with precordial pain associated with High Blood Pressure, showed 88.9% positive results in the test. Positive results were higher in women in the rest of the combinations of alterations. (See Figure 5)

Conclusions

1. High positivity rates in women were the result of false positives.

2. High blood pressure in women, and smoking and Diabetes mellitus in men, showed significant risk.

3. Precordial pain during the test had statistical significance for both sexes, as was the case of high blood pressure in women and arrhythmias in men.

4. Occupation and accompanying symptoms did not influence a high positive rate in the Diagnostic Ergometric Test in women.

Recommendations

It is necessary to incorporate effort echocardiography in procedures for the positive diagnosis of ischemic heart disease in women. This will contribute to understanding the medications and work and social limitations for those patients whose diagnosis was based on ergometric testing.

References

1. Alegría E, Alzamora P, Bolao IG, Fidalgo ML. Cardiopatía Isquémica en la mujer. Rev Española de Cardiología 1991; Vol. 44 No 8: 500-10.

2. Maroto SM. Particularidades en el diagnóstico de la cardiopatía isquémica en la mujer. Rev Española de Cardiología 1994; Vol. 47 No 3: 13-16.

3. Abadal LT. Riesgo cardiovascular en la menopausia: mito, paradoja o realidad. Importancia de las relaciones clínicas frente a la interpretación de los datos estadísticos. Rev Española de Cardiología 1999; Vol. 52 No 52: 463-66.

4. Alvarez M. Hábito de fumar y Cardiopatía Isquémica. Trabajo de Terminación de Residencia para optar por el titulo de Especialista 1er Grado en Medicina Interna. FCM Matanzas, 1996.

5. Torney L, Papadakis M. Síndrome Menopáusico. In: Diagnóstico Clínico y tratamiento. Editorial El Manual Moderno. 32 Ed. México,1997:680-1

6. Sytkowski PA, D'Agostino RB, Belanger A, Kannel WB. Sex and time trends in cardiovascular disease incidence and mortality: The Framingham Heart Study, 1950-1989. Am.J.Epidemiol. 1996;143:338-350.

7. Kannel WB. Blood pressure as a cardiovascular risk factor. Prevention and treatment. JAMA 1996;275:1571-1576.

8. Bennet SC, Plum F. Menopausia y Postmenopausia. In: Cecil. Tratado de Medicina Interna. Editorial McGraw-Hill Interamericana. 20 Ed. México,1997:1512-3

Further references:

MINSAP. Programa Nacional de Control, Tratamiento y Evaluación de la Cardiopatía Isquémica. La Habana, 2000.
Wilson PWF. Metabolic risk factors for coronary heart disease: current and future prospects. Curr Opin Cardiol 1999; 14:176-185.
D'Agostino RB, Russell MW, Huse DM, Ellison RC, Silbershatz H, Wilson PWF et al. Primary and subsequent coronary risk appraisal: new results from the Framingham Study. Am Heart J 2000; 139:272-281.
Moore LL, Visioni AJ, Wilson PWF, D'Agostino RB, Finkle WD, Ellison RC. Can sustained weight loss in overweight individuals reduce the risk of diabetes mellitus? Epidemiology 2000; 11:269-273.
Meigs JB, Mittleman MA, Nathan DM, Tofler GH, Singer DE, Murphy-Sheehy PM et al. Hyperinsulinemia, hyperglycemia, and impaired hemostasis: the Framingham Offspring Study. JAMA 2000; 283:221-228.

Authors:

1.- First and Second Degree Specialist in Internal Medicine, Faustino Perez University Hospital, Matanzas.

2.- First and Second Degree Specialist in Cardiology, Faustino Perez University Hospital, Matanza

3.- First Degree Specialist in Family Medicine, Provincial Center of Hygiene and Epidemiology; Matanzas