Anesthetic Management of Peripartum Cardiomyopathy (PPCM)
➧ It is a form of heart failure affecting females in their last months of pregnancy or early puerperium.
➧ The role of the anesthesiologist is important in the peri-operative and ICU.
Diagnostic Criteria for PPCM:
➧ Development of heart failure within the last month of pregnancy or 6 months postpartum.
➧ Absence of any identifiable cause for heart failure.
➧ Absence of any heart disease before the last month of pregnancy.
➧ Echo- Criteria of LV 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 HTN, Pre-eclampsia, C.S.
-Poor antenatal care, Breastfeeding.
-Alcohol, Cocaine, and Tobacco abuse.
Incidence:
-1 in 4,000 live births.
-This wide variation may be explained by the influence of genetic and environmental factors, as well as different reporting patterns and diagnostic criteria used.
Etiology:
1) 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 PPCM may lead to Histological changes resembling myocarditis.
2) Viral Infection
-During pregnancy, there is a degree of depressed immunity 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.
3) Autoimmune Theory
-Studies hypothesized, that fetal cells may escape to the systemic circulation triggering an immune response.
-Higher rates of PPCM with twin pregnancies and its familial predisposition support this theory.
4) Inflammatory Cytokines
-In PPCM patients, higher concentrations of inflammatory cytokines like TNF α, CRP, and IL-6 were found. CRP levels correlated inversely with left ventricular ejection fraction (LVEF).
5) Selenium Deficiency
-Significantly low selenium concentrations in PPCM patients were found, still, this might be a mere incidental association rather than a cause.
6) Exaggerated Hemodynamic Response
-In pregnancy, there are physiologic changes in the CVS. It has been postulated that PPCM may be an exacerbation of this normal phenomenon.
7) Prolonged Tocolytic Therapy
-Usually, tocolysis causes tachycardia and vasodilation, so it may actually unmask existing heart disease rather than play an etiologic role.
Diagnosis:
-The symptoms & signs are the same as heart failure.
-You have to exclude other causes of heart failure as valvular and IHD.
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.
Signs:
-Blood pressure may be normal/elevated/low.
-Tachycardia, Gallop rhythm.
-Engorged neck veins, Pedal edema
-Clinically, the heart may be normal or there may be mitral and/or tricuspid regurgitation with pulmonary crepitations.
Investigations:
➧ ECG: No specific findings.
➧ Chest x-ray: May show: Cardiomegaly, Pulmonary venous congestion.
➧ Echocardiography: It is the most important diagnostic tool, and assesses the severity and the prognosis of PPCM.
Echo findings are:
-Decreased LVEF and LVFS, Increased LVEDD.
-Dilatation of all cardiac chambers with subsequent functional mitral, tricuspid, pulmonary and aortic regurgitation.
➧ Dobutamine stress Echo: is a better prognostic tool than the ordinary Echo.
➧ TEE and Cardiac MRI: are better tools for detecting intramural thrombi than the ordinary Echo.
Complications:
1-Thromboembolism
-Thrombi often form in patients with LVEF < 35% and are associated with a mortality rate of 50%.
2-Arrhythmias
-All kinds of arrhythmias have been reported up to VT and heart arrest.
3-Organ failure
-Acute liver failure and hepatic coma due to passive liver congestion secondary to cardiac failure. Also, multiorgan failure may occur.
4-Obstetric & Perinatal complications
-There is an increased incidence of Abortion, Premature deliveries, IUGR, and Intrauterine fetal deaths.
Management:
A) Non-pharmacological measures:
-As with any heart failure, salt and water restriction (2-4 g/d., 2 L/d.).
-Once the severe symptoms are improved, modest exercise should be encouraged.
B) Pharmacological measures
-As with any heart failure: (Digoxin, Diuretics, VD, and Anticoagulation) are the mainstay.
-But we have to consider the safety of these drugs in pregnancy and lactation:
1-Digoxin
-It is a class C drug but presumed safe in low doses.
-In a pregnant female, the serum level should be monitored.
-Some studies claimed that digoxin for 6 m. decreases the risk of recurrence of PPCM.
2-Diuretics
-They are safe during 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 is better avoided during pregnancy.
-Should be used with caution not to induce dehydration and uterine hypoperfusion. Also, metabolic alkalosis may develop.
3-Vasodilators
-They reduce the preload and afterload in heart failure, and so increase the CO.
-Hydralazine and Nitrates are the VD of choice during pregnancy.
-ACEI and ARB are the mainstays in heart failure but they are class D, and contraindicated in pregnancy due to teratogenicity. So, they are considered after labor, but breastfeeding has to be discontinued.
4-Calcium Channel Modulators
-Calcium channel blocker: Although has –inotropic, but has been shown to improve the survival in cardiomyopathy patients. it also reduces the level of inflammatory cytokines so they would play an important in PPCM.
-Levosimendan: is especially valuable and used with success in PPCM. but again, breastfeeding should be avoided during its use.
5-Beta Blockers
-Like CCB, BB now has an important role in heart failure and they are not contraindicated in pregnancy, though associated with low birth weight.
-Both BB and ACEI have an additional role in immunosuppression and prevent remodeling and reduce ventricular dimensions.
6-Antiarrhythmic agents
-No antiarrhythmic agent is completely safe in pregnancy.
-Quinidine and Procainamide have a 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.
7-Anticoagulation therapy
-Anticoagulation therapy targets patients with LVEF < 35%, bedridden, Atrial fibrillation, Mural thrombi, Obese, or with a history of thromboembolism.
-The therapy may persist for as long as 6 w. in the Puerperium.
-Heparin is used in the antepartum and Heparin or Warfarin is used 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 pt. condition deteriorates despite maximal medical management.
-If the pt. is compensated, normal vaginal delivery is preferred.
-If the patient is severely decompensated or there are obstetric indications, C.S. should be done.
-In both cases, the pt. should be admitted to ICU for early detection of complications.
Anesthetic management:
A) Anesthesia for Vaginal Delivery:
-Controlled epidural a. 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.
B) Anesthesia for Cesarean Section:
Both General anesthesia (GA) and Regional a. (RA) have been used.
1-Regional Anesthesia
-Single-shot spinal a. is not preferred, because of its rapid hemodynamic changes and hypotension.
-Epidural a. is used because of its better hemodynamic stability.
-Continuous spinal a., 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 pt.: Local infiltration with Bilateral ilioinguinal blocks has been used.
2-General Anesthesia
-GA may be needed in emergency situations or when RA is contraindicated, particularly in the anticoagulated patient.
-Advantages: Airway control and ventilation, and it facilitates the use of TEE.
-Disadvantage: It can cause maternal and fetal cardiorespiratory depression, and the stress of rapid sequence induction on the decompensated heart could be dangerous. There is also an 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 fatal respiratory depression.
-Monitoring: 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 an arterial line and may be a pulmonary artery catheter.
C) Postoperative management:
-All PPCM patients should be managed in an ICU as they are prone to develop LVF and pulmonary edema during 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 w.) after delivery.
-Coexisting medical illness.
-Delay of initiation of medical treatment.
-Intracardiac thrombi, Conduction defects, Persistence of ventricular dysfunction > 6 m.
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 the dobutamine stress test.
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