Patient Information Sexual activity in patients with cardiovascular disease

INTRODUCTION—Sexual activity is an important component of quality of life and thus is of great concern for both patients with heart disease and their physicians. Cardiac patients are often fearful of triggering myocardial infarction (MI) during intercourse and may therefore have sex less frequently. Another component of this problem is that patients seeking medical attention for sexual dysfunction often have concomitant cardiovascular disease.

Several aspects of the sex-MI relationship will be discussed here, including the cardiovascular effects of sexual activity, the association between sex and MI, modulating factors that may decrease the risk of MI following sexual activity, and the treatment options for cardiac patients with sexual dysfunction. The risk in patients with other cardiovascular diseases will also be mentioned.

CARDIOVASCULAR EFFECTS OF SEXUAL ACTIVITY—Sexual activity, including arousal, erection, ejaculation, orgasm, refractory period, and resolution, is in part dependent upon changes in the autonomic nervous system.

  • Sexual arousal and penile erection in men results from stimulation of parasympathetic nerves in the penis, reduced activity of sympathetic pathways, and the release of nitric oxide from the endothelium The importance of nitric oxide constitutes the rationale for the use of sildenafil in men with sexual dysfunction. Early sexual arousal in women appears to result from sympathetic nervous system activation

The main outflow to the cardiovascular system during sexual intercourse is sympathetic and is mediated by outputs from the brain carried by efferent pathways originating from the thoracic spinal cord .

Hemodynamic stress—Early studies, performed during sexual activity in volunteers who were monitored in the laboratory, found the following changes during orgasm

  • Peak heart rates were 140 to 180 beats per minute
  • The mean increase in blood pressure was 80/50 mmHg
  • Respiratory rates and tidal volumes increased significantly, approaching values seen with moderately severe physical exertion

This perception of a high cardiac workload and risk associated with sexual intercourse was reinforced by the observations that patients with stable angina often noted chest discomfort during or immediately after intercourse.

However, the results were different in studies performed in "real-life" settings, in which married couples were monitored during sexual intercourse in their own bedrooms . The mean heart rate at the time of orgasm was 117 beats per minute, which was lower than the heart rate during normal daily activities (mean 120 beats per minute). Although the blood pressure was not measured in these studies, the mean estimated blood pressure was 162/89 mmHg. This value was based upon the blood pressure achieved during exercise to a heart rate similar to that during orgasm. Although such a calculation might underestimate the peak blood pressure at the time of orgasm, because it does not account for the sympathetic response to arousal and intercourse, similar values were noted in another study in which the blood pressure was measured

The standard clinical measure of exertion is the MET (metabolic equivalent of oxygen consumption); 1 MET is defined as 3.5 mL O2 uptake/kg per min, which is the resting oxygen uptake in a sitting position. Sexual activity is often equated with 2 to 3 METS during the preorgasmic phase and 3 to 4 METS during orgasm; this is equivalent to walking at two to four miles per hour on a level surface Exercise testing is often used to assess both exercise tolerance and tolerance for sex

The clinical implication of these observations is that sexual intercourse is associated with a modest increase in myocardial oxygen demand that lasts only a brief timeThis has been confirmed in a number of studies that found that sexual activity contributes to only a small percent of infarctions

Other reports have evaluated the effect of exercise training and sexual position on the cardiovascular response to sexual activity. Exercise training attenuates the heart rate responseand reduces the small risk of MI following sex (see below). In one report, 16 patients with MI underwent a 16 week exercise training programThe mean peak heart rate during orgasm was significantly lower after exercise training (120 versus 127 beats per minute prior to training) and maximal oxygen consumption increased by 11.5 percent. There was no change in heart rate or oxygen consumption in six control patients.

It has been assumed that the man would perform less physical work during sexual intercourse if he were supine. However, this does not appear to be important. In one study of eight normal men who were monitored during sexual intercourse with their wives in their bedrooms, there was no difference in heart rate (114 versus 117 beats per minute) or blood pressure (163/81 versus 161/77 mmHg) between man on top or man on bottom A second study found a slightly lower minute oxygen consumption for men in the supine position, but this lasted for only a brief period during orgasm.

Response in stable angina—During sexual intercourse, the increase in heart rate and blood pressure is the same as any fonof exercise. Thus, patients with angina may become symptomatic during intercourse. I one series of 35 such patients who were monitored during intercourse in their homes, 65 percent complained of angina on at least some occasions and had to stop activity

Appropriate medical therapy, usually beta blockers and, in some cases, prophylactic sublingual nitrates, can prevent angina in these patients and permit a normal sex life Patients with chronic coronary disease who undergo revascularization with a percutaneous coronary intervention or bypass surgery and who are asymptomatic do not have an increased risk of symptoms during sexual intercourse.

RISK OF MI AFTER SEX—In order to determine the relative risk of myocardial infarction (MI) following sex, a case-crossover design has been used. With this method, each patient serves as his or her own control [. As a result, the effect of confounding chronic risk factors is virtually eliminated, which is important because people who are sexually active may be different from those who are not sexually active in ways that would be difficult to account for if different individuals were selected for the control group.

The case-crossover design was used in the Determinants of Myocardial Infarction Onset Study of 1774 patients who were interviewed with one week of an acute MI; 858 patients were sexually active . The following findings were noted:

  • The relative risk of MI within two hours after sexual activity was 2.5; there was no increased risk of MI beyond this time period. The risk was reduced in patients who underwent regular exercise.
  • The relative risk of MI after sexual activity was similar in patients with a history of prior angina or MI or no prior cardiac disease.
  • Only 9 percent of patients had sex in the 24 hours before MI and only 3 percent in the important two hour time period. As a result, the absolute increase in risk was small, as sexual activity appeared to contribute to the onset of MI in only 0.9 percent of patients. Many other triggers of an MI, such as psychologic stress, anger, or physical activity may cause a greater increase in absolute risk because they occur more frequently

The results were similar in a second case-crossover study of 699 patients . Only 1.3 percent had sexual intercourse within two hours of an MI; the estimated relative risk of an MI in the hour after sexual intercourse was 2.1 overall and 4.4 in those with a sedentary lifestyle.

Although sexual activity can trigger an MI, what is important to the individual is the absolute increase in risk (ie, the risk from sex minus the risk at all other times, referred to as the "attributable risk").

Since sexual activity is a transient trigger that increases risk for only a two hour period, the absolute increase in risk is very small. Based upon the result from the Determinants of Myocardial Infarction Onset Study a 50 year-old man free of cardiac disease with an annual baseline risk of MI of 1 percent would increase his annual risk of MI to only 1.01 percent from weekly sexual activity [Even a person with a high annual risk for an MI of 10 percent would increase the annual risk to only 10.1 percent from weekly sexual activity.

Modulation of risk—Two factors appear to modulate the risk of MI after intercourse: exercise and medical therapy.

Regular exercise—In both of the case-crossover studies described above, the risk of MI following sexual activity was reduced in patients who exercised regularly In an analysis from the Determinants of Myocardial Infarction Onset Study, regular physical exercise at levels of ≥6 METs modified the association between sex and MI he more regularly a person exercised, the lower their relative risk of MI from sexual activity.

These findings are consistent with observations that regular exercise reduces the risk of triggering MI and sudden death from heavy physical exertionand that exercise training increases the aerobic capacity and decreases the peak heart rate in post-MI subjects engaging in sexual intercourse . In another analysis from the Determinants of Myocardial Infarction Onset Study, 4.4 percent of patients with an acute MI reported heavy physical exertion within one hour of the MI, with symptoms usually beginning during exertion (relative risk 5.9 compared with less strenuous or no physical exercise) . Importantly, the relative risk was inversely related to the degree of regular exercise before the MI, ranging from 2.4 to 107 in patients who usually exercised five or more times per week or less than once per week, respectively. Thus, people who have been physically and sexually inactive may require more careful medical advice and monitoring prior to resuming sexual activity.

Medical therapy—Other potential modifiers of risk may be hypothesized from studies of patients with an MI and the proposed pathophysiology of triggering factors . The increased relative risk of MI from sexual activity makes it similar to other triggers of MI. Among the proposed triggers are enhanced hemodynamic stress, resulting from an increase in heart rate, blood pressure, and myocardial oxygen demand, as well as increased platelet aggregability and coagulation in combination with a coronary artery plaque that is vulnerable to rupture

As a result, medications that reduce heart rate or blood pressure or inhibit platelet aggregation may reduce the risk of triggers of MI.

  • Beta blockers reduce myocardial oxygen demand and can minimize or eliminate angina during sexual intercourse. The Determinants of Myocardial Infarction Onset Study found that beta blockers reduced the risk of MI following anger but not sexual intercourse
  • Aspirin lowers the risk of MI following episodes of angerand the morning waking hours both of which are known triggers of MI. In the Determinants of Myocardial Infarction Onset Study, aspirin therapy was associated with a nonsignificant reduction in the relative risk of MI following sexual activity

RISK OF SEXUAL ACTIVITY—Although the risk of a myocardial infarction (MI) or other cardiac event (angina, arrhythmias, exacerbation of heart failure) associated with sexual activity is low, there may be an increased risk in patients with a high risk cardiovascular profile or those with established disease.

Risk assignment—An assessment of sexual function should be performed routinely in the initial evaluation of all patients with cardiovascular disease. Further clinical evaluation is based upon estimated risk, which must be individualized to any particular patient.

In 2005, the Second Princeton Consensus Panel on sexual activity and cardiac risk published recommendations for the initiation or resumption of sexual activity and for the management of sexual dysfunction in patients with cardiovascular disease The recommended therapeutic approach, which is described below, was related to estimated risk

Low risk—The large majority of patients are at low risk. This includes patients with:

  • No symptoms and less than three cardiovascular risk factors (excluding gender)
  • Controlled hypertension
  • Mild, stable angina, although the antianginal regimen may need to be altered (ie, no nitrates) in patients who are treated with a phosphodiesterase-5 inhibitor for erectile dysfunction (see 'Adverse interaction with nitrates' below)
  • Successful coronary revascularization
  • An MI more than six to eight weeks previously in patients who are asymptomatic and do not have exercise-induced ischemia or have undergone coronary revascularization; it is probably safe to resume sexual activity three to four weeks after the MI in patients who have undergone successful revascularization and in patients without exercise-induced ischemia
  • Mild valvular disease

Patients at low risk can be safely encouraged to initiate or resume sexual activity and can be treated for sexual dysfunction.

There are limited data on patients with pericarditis, mitral valve prolapse, or atrial fibrillation with a controlled ventricular response. These patients are not at high risk and should be managed on an individualized basis.

Intermediate or indeterminate risk—Intermediate risk includes patients with:

  • No symptoms and three or more cardiovascular risk factors (excluding gender); a sedentary lifestyle is considered a risk factor
  • Moderate, stable angina
  • A recent MI (more than two weeks but less than six weeks); as noted above, in patients who have not undergone revascularization, the risk can be assessed with stress testing, which is often performed during this period
  • Asymptomatic left ventricular dysfunction with left ventricular ejection fraction <40 percent or New York Heart Association class II heart failure (table 2)
  • Noncardiac manifestations of atherosclerotic disease, such as peripheral vascular disease or prior stroke or transient ischemic attack.

Patients at intermediate or indeterminate risk should receive further evaluation, such as stress testing, particularly in patients with a sedentary lifestyle, which may permit restratification into the low risk or high risk category. Consultation with a cardiologist may be useful in some cases for assessing risk and management.

High risk—High risk includes patients with:

  • Unstable or refractory angina
  • Uncontrolled hypertension
  • New York Heart Association class III or IV heart failure
  • An MI within the past two weeks
  • High-risk arrhythmias
  • Obstructive hypertrophic cardiomyopathy
  • Moderate-to-severe valvular disease, particularly aortic stenosis

Patients at high risk should be stabilized by appropriate therapy and further risk stratified before resuming sexual activity.

As described below, treatment with a phosphodiesterase-5 (PDE-5) inhibitor such as sildenafil is contraindicated in patients taking a nitrate. (See 'Adverse interaction with nitrates' below.)

SEXUAL DYSFUNCTION POST-MI—Sexual dysfunction is common in patients with cardiovascular disease because of concern about risk; side effects of medications (diuretics, beta blockers, lipid-lowering drugs); the coexistence of shared risk factors, such as lipid abnormalities, diabetes, smoking, and hypertension; and the presence of psychologic factors Sexual dysfunction after a myocardial infarction (MI) (most often erectile dysfunction in men) is estimated to occur in one-half to three-quarters of patients; although less common, sexual dysfunction is also seen after bypass surgery Both men and women have less sexual activity and less satisfaction with sexual activity after an MI

Cardiac patients may have psychologic causes for sexual dysfunction, which are often due to perceptions of their illness and should be ascertained in the history [33]. Worries about triggering an MI or sudden death and depression and anxiety about a newly diagnosed illness, especially the occurrence of an MI, can all contribute to sexual dysfunction in patients with heart disease [28,29,34-36]. In a report of 130 women with an MI, for example, 71 percent noted a decrease in or no sexual activity, often due to fear on the part of the patient or spouse [29].

Unfortunately, many physicians do not discuss this issue of sexual intercourse with post-MI patients or their spouses [For these patients, attendance at cardiac rehabilitation, treatment of any psychiatric condition, and reassurance of the low attributable risk of MI may improve sexual function []. (Since sexual activity is often equated with physical activity, exercise testing is often used to measure exercise tolerance and tolerance for sex

TREATMENT OF SEXUAL DYSFUNCTION—Sexual function is an important component of quality of life and subjective well-being. The prevalence of sexual dysfunction, especially erectile dysfunction in men, is higher in those with cardiovascular disease than in the general population. General issues about the evaluation and management of sexual dysfunction in men and women are discussed more fully elsewhere. General principles—The management of sexual dysfunction in patients with cardiovascular disease is based in part upon the estimated risk as described above. (See 'Risk of sexual activity' above.)

The following recommendations from the Second Princeton Consensus Panel are primarily based upon patients with known coronary heart disease (angina, MI, post bypass surgery) but must be individualized to any particular patient ]. Perhaps the greatest cardiovascular risk is the enabling of moderate exercise (via sexual activity) in previously inactive patients

  • Low risk — Such patients can be safely encouraged to initiate or resume sexual activity or to receive treatment for sexual dysfunction.
  • Intermediate risk — Such patients should receive further evaluation in order for restratification into a low risk or high risk category. This is often achieved by stress testing, particularly in patients with a sedentary lifestyle. Consultation with a cardiologist may be useful in some cases for assessing risk and management.
  • High risk — Such patients should be stabilized by appropriate therapy and further risk stratified before resuming sexual activity or being treated for sexual dysfunction.

An important component of the treatment of sexual dysfunction in all patients is correction of reversible causes. In patients with heart disease, this includes reassurance in patients in whom sexual activity is considered to be safe (see 'Risk of sexual activity' above) and drug-induced side effects.

Among the cardiovascular drugs that may be implicated are thiazide diuretics, beta blockers, and lipid-lowering drugs ]. Consideration should be given to the time sequence of initial symptoms and changes in a patient's medications, and, when possible, alternative prescriptions should be pursued.