Anesthetic management of peripartum cardiomyopathy

by Dr/ Amr Maher mahmoud .Lecturer of anesthesia

It is a form of heart failure affecting females in their last months of pregnancy or early puerperium.(1)

The role of anesthesiologist is important in the peri-operative and the intensive care unit.

Diagnostic criteria for PPCM:

Development of heart failure within last month of pregnancy or six months postpartum.

Absence of any identifiable cause for heart failure

Absence of any heart disease before last month of pregnancy.

Echocardiographic criteria of left ventricular dysfunction:Ejection fraction < 45%Left ventricular fractional shortening < 30%.Left ventricular end-diastolic dimension > 2.7 cm/m2 BSA

Risk factors:

Black race, family history.

Advanced maternal age.

Multiparity, multiple gestations.

Obesity, malnutrition.

Gestational hypertension, preeclampsia, cesarean section.

Poor antenatal care, breast feeding.

Alcohol, cocaine and tobacco abuse.(1)

Incidence:

1 in 4,000 live births.

This wide variation may be explained by the influence of geneticand environmental factors, as well as different reporting patterns and diagnostic criteria used.(1)

Etiology:-

Myocarditis:-

• It is not known whether it is an association or a cause.

• Only diagnosed by histological examination of endometrial biopsy.

• also, the vasopressor therapy in PPC may lead to a Histological changes resembling myocarditis.

Viral infection

• During pregnancy, there is a degree of depressedimmunity that may lead to viral infection. Viral infection has been implicated as a cause of myocarditis that would lead to cardiomyopathy.

• On the other hand, it has been argued that viral cardiomyopathy should not be included as a cause of PPCM. But rather a separate entity.

Autoimmune theory:

• Studies hypothesized, that fetal cells may escape to the systemic circulation triggering immune response.

• Higher rates of PPCM with twin pregnancies and its familial predisposition supports this theory.

Inflammatory cytokines:

• In PPCM patient, higher concentrations of inflammatory cytokines like TNF α, CRP, IL-6 were found. CRP levels correlated inversely with left ventricular ejection fraction (LVEF).(1)

Selenium deficiency:

•Significantly low selenium concentrations in PPCM patients was found, still, this might be a mere incidental association rather than a cause.

Exaggerated hemodynamic response

•In pregnancy, there is physiologic changes in the C.V.S. (1)

It has been postulated that PPCM may be an exacerbation of this normal phenomenon.

Prolonged tocolytic therapy

• Usually tocolysis causes tachycardia and vasodilation, so it may actually unmask existing heart disease rather than play anetiologic role.

Symptoms

• Dyspnea on exertion, cough, orthopnea and paroxysmal nocturnal dyspnea, resembling left sided heart failure.

• Non specific symptoms include palpitations, fatigue, malaise and abdominal pain.

• Embolic manifestations may be present, as mural cardiac thrombi commonly occur. The patient may complain of chest pain, hemoptysis and hemiplegia, rarely myocardial infarction may be the presentation due to coronary embolism.

Diagnosisthe S&S are basically the same S&S of heart failure.

We have to exclude other causes of heart failure as valvular and ischemic heart diseases.

Signs

•Blood pressure may be normal, elevated or low.

•Tachycardia, gallop rhythm.

•engorged neck veins and pedal edema

•Clinically, the heart may be normal or there may be mitral and/or tricuspid regurgitation with pulmonary

crepitations(1)

Investigations

• ECG….. No specific findings.

• chest x-ray…. May show cardiomegaly, pulmonary venous congestion.

•Echocardiography…. It is the most important diagnostic tool, and assess the severity and the prognosis of PPCM.

• Dobutamine stress Echo is a better prognostic tool than the ordinary Echo,(1) TEE and cardiac MRI are better tools in detecting intramural thrombi than the ordinary Echo.

• Echo findings are :-

oincreases LVEDD, decreased LVFS and LVEF.

odilatation of all cardiac chambers with subsequent functional mitral, tricuspid, pulmonary and aortic regurgitation.

COMPLICATIONS

Thromboembolism

•Thrombi often form in patients with LVEF < 35% and associated with mortality rate 50%.(1)

Arrhythmias

• all kinds of arrhythmias have been reported up to ventricular tachycardia and heart arrest.(@)

Organ failure

• Acute liver failure and hepatic coma d.t passive liver congestion secondary to cardiac failure. Also, multiorgan failure may occur.

Obstetric & perinatal complications

• There is increased incidence of abortion, premature deliveries, intrauterine growth retardation, or intrauterine fetal deaths.

Management

Non pharmacological measures

• As any heart failure, salt and water restriction (2-4 gm/day,, 2 L/day).

• Once the severe symptoms are improved, modest exercise should be encouraged. (1)

Pharmacological measures

• As any heart failure; digoxin, diuretics, vasodilators and anticoagulation are the mainstay. But we to consider the safety of these drugs in pregnancy and lactation.

• Digoxin

It is a class C drug, but presumed safe in low doses.

In pregnant female, the serum level should monitored. (1)

Some studies claimed that digoxin for 6 month decreases the risk of recurrence of PPCM.

• Diuretics

They are safe in pregnancy and lactation.

Aim to reduce preload .

Usually, loop diuretics are used and thiazides are used in milder cases. spironolactone is very beneficial in heart failure, but better avoided in pregnancy.

Should be used with caution not to induce dehydration and uterine hypoperfusion. Also, metabolic alkalosis may develop.

Continue diuretics

• Vasodilator

They reduce the pre and after load in heart failure, and so increase the C.O.

Hydralazine and nitrates are the vasodilator of choice during pregnancy.

ACEI, and ARB are mainstay in heart failure but they class d, and contraindicated in pregnancy due to teratogenicity. So, they are considered after labour, but breast feeding has to be discontinued.

• calcium channel modulators

Calcium channel blocker, though has –ve intropism, but has been shown to improve the survival in cardiomyopathy patients. it also reduces the level of inflammatory cytokines so they would play important in PPCM.

Levosemindane is especially valuable and used with success in PPCM. but again, breast feeding should be avoided during its use.(1)

Both BB, and ACI have an additional role in immunosuppression and prevent remodeling and reduce ventricular dimensions.

• Beta Blockers

like CCB, BB now has important role in heart failure and they are not contraindicated in pregnancy, though associated with low birth weight.

• Antiarrhythmic agents

No antiarrhythmic agent is completely safe in pregnancy.

Quinidine and Procainamide, has high safety profile, but treatment should always start in a hospital because of the high incidence of torsades de pointes.

Amiodarone may cause hypothyroidism, growth retardation and perinatal death, so it should be reserved for life threatening arrhythmias only.

•Anticoagulation therapy

Anticoagulation therapy targets patients with LVEF less than 35%, bedridden, with atrial fibrillation, mural thrombi, obese, or with history of thromboembolism.

The therapy may persist for as long as six weeks in the Puerperium.

Heparin is used in the antepartum and heparin or warfarin isused in the postpartum period as warfarin is contraindicated in the antepartum period due to its teratogenicity.

OBSTETRIC MANAGEMENT

•induction of delivery should be considered if a patient’s condition deteriorates despite maximal medical management.

• If the patient is compensated, normal vaginal delivery is preferred, while if the patient is severely decompensated or there is obstetric indications, cesarean section should be done.(1)

• In both cases, the patient should be admitted to ICU for early detection of complications.

ANESTHETIC MANAGEMENT

Anesthesia for vaginal delivery:

Controlled epidural analgesia under invasive monitoring is a safe and effective method.

Sympathectomy induced by epidural leads to afterload and preload reduction that improves myocardial function in PPCM patients.

Anesthesia for cesarean section:

Both general anesthesia (GA) and regional anesthesia (RA) have

been used.

• Single shot spinal anesthesia is not preferred, because of its rapid hemodynamic changes and hypotension.

• Epidural anesthesia is used because of its better hemodynamic stability.

• Continuous spinal anesthesia , with its lower failure rates, faster onset, good muscle relaxation, less drug requirement, postoperative analgesia facilities and better maintenance of hemodynamics has also been successfully applied.

• In severely compromised patients, local infiltration with bilateral ilioinguinal bloacks have been used.

Regional anesthesia

General anesthesia

• GA may be needed in emergency situations or when RA is contraindicated, particularly in anticoagulated patients

• GA has the advantages of airway control and ventilation, and it facilitates the use of transesophageal echocardiography

• GA has the disadvantage that it can cause maternal and fetal cardiorespiratory depression, and the stress of rapid sequence induction on decompensated heart could be dangerous. There is also increased risk of LVF and pulmonary edema. GA does not provide thromboprophylaxis like RA.

• Opioid-based anesthesia may be advantageous in compromised cardiac conditions, but carries a high risk of fetal respiratory depression.(1)

• in mild cases, noninvasive monitoring can be used. in severely decompensated cases, the use of invasive monitoring is a must. This includes the use of arterial line and may be pulmonary artery catheter.

Postoperative management

• All PPCM patients should be managed in an ICU as they are prone to develop LVF and pulmonary edema in this period. Also, to monitor the possible complications.

• Postoperative pain can be managed by RA or parenteral opioid-based techniques.

Prognosis

Poor prognosis criteria

The worst prognosis is found in patients with:-

•Higher age and parity, multiple gestations.

•Black race.

•Later onset of symptoms (> 2 weeks) after delivery.

•Coexisting of medical illness.

•Delay of initiation of medical treatment.

•Intracardiac thrombi, conduction defects, or persistence of ventricular dysfunction for more than 6 months.

RISK OF RECURRENCE IN SUBSEQUENT PREGNANCY

The highest risk of recurrence remains in patients with persistent cardiac dysfunction and the lowest risk is in those whose cardiac functions have been normalized, as evidenced by dobutamine stress test

Thank you