Peripartum Cardiomyopathy

/

What is Peripartum Cardiomyopathy? 

  • Definitions:

    • Potentially life-threatening pregnancy-associated disease that typically arises in the peripartum period and is marked by left ventricular dysfunction and heart failure - from Arany Z, Elkayan U. Peripartum Cardiomyopathy in Circulation from April 2016.

      • It’s not a precisely defined entity, because timing can vary. 

    • The US National Heart, Lung, and Blood Institute (NHLBI) in the 1990s defined PPCM as heart failure that develops in the last month of pregnancy or up to 5 months postpartum

      • This excludes patients that have pre-existing cardiomyopathies, but there are patients who otherwise meet criteria for PPCM who are <36 weeks.

    • Many definitions require cardiomyopathy to demonstrate reduced LV systolic function, where LVEF < 45%, fractional shortening <30%, or both.

  • Epidemiology:

    • Ranges from 1/1000 to 1/4000 live births, but potentially increasing.

    • Proposed reasons: 

      • Increasing maternal age, preeclampsia, and multiple gestations, which are all risk factors for PPCM.

      • Also increasing HTN, diabetes, and obesity.

      • Also just growing recognition of PPCM as a disease entity.

  • Symptoms/Signs:

    • Usual symptoms of heart failure:

      • Ie. fatigue, shortness of breath, increased extremity swelling, sometimes arrhythmias from overstretching of the heart.

    • Signs on exam:

      • Evidence of left sided congestion (pulmonary rales), right side congestion (ie. increased JVP and edema) 

      • Elevated BNP (Malhame in Green Journal 2019) 

      • EKG may show non-specific changes like LBBB pattern

      • Chest Xray: may show pulmonary edema and enlarged cardiac silhouette 

      • Echo: LV dilation of variable degrees, LV systolic dysfunction, RV and bi-atrial enlargement; LVEF < 45%  

What causes PPCM? 

  • Older hypothesis: triggered by viral myocarditis 

    • However, a study that looked at endomyocardial biopsies in patients with PPCM and other types of cardiomyopathies, the same proportion of specimens in each group had detectable viral genomes (30%).

  • Current hypothesis: “two hit” model 

    • Vascular insult - due to antivascular or hormonal effects of late pregnancy and early postpartum period → cardiomyopathy in women with an underlying predisposition.

    • There is also question of genetic predisposition 

    • High prevalence of pre-eclampsia in women with PPCM suggests a possible shared pathophysiology - perhaps some type of placental angiogenic factor.

How do we manage PPCM? 

  • Prognosis: 

    • 50-80% of women with PPCM recover to normal range LVEF (>50%) with most recovery occurring within the first 6 months.

      • This is pretty good considering that in the early 1970s, the mortality of PPCM was 30-50%.

    • LV size and EF at time of diagnosis most strongly predict LV recovery.

      • LVEF <30% and LV end-diastolic diameter > 6 cm are indicative of decreased likelihood of left ventricular recovery and increased risk of mechanical support, transplant, and death.

    • 25% of patients will develop chronic heart failure, and mortality rate is still 6-10% in the United States (depending on follow up defined for mortality rate by study).

  • Complications

    • One study found that 2.6% of women with PPCM in the US had cardiogenic shock, 1.5% of them needed mechanical circulatory support, and 0.5% of women underwent cardiac transplantation.

    • VTE is one of the most common severe complications of PPCM - affect 6.6% of women.

      • Mechanism: underlying intracardiac thrombosis in PPCM d/t cardiac dilatation and hypocontractility → blood stasis.

      • Also pregnancy is a hypercoagulable state.

    • Arrhythmias - can contribute to morbidity and mortality d/t death from VTach.

      • 2.1% of women with PPCM had cardiac arrest and 2.9% underwent implantation of a cardiac device.

  • Treatment 

    • Few studies performed specifically in women with PPCM, so management strategies are generally extrapolated from other forms of heart failure.

    • Multidisciplinary care: MFM, anesthesia, and cardiology.

    • Individualized discussion of delivery timing for optimal maternal-neonatal outcome.

    • Usually don’t need to do a cesarean.

      • Hemodynamic shifts may be mitigated by slow epidural and assisted second stage of labor.

    • Care overall is usually supportive, directed toward managing heart failure symptoms.

      • Diuresis (but don’t go overboard and cause hypotension) 

      • If hemodynamics permit, beta blockers should be used, with preference of B1 selective ones (ie. metoprolol).

        • B2 blockers may prompt uterine activity, so better to avoid.

      • ACE-inhibitors and ARBs are considered contraindicated in pregnancy, but can use them postpartum.

      • Consider anticoagulation in PPCM if LVEF < 30% 

      • If arrhythmias, may require acute or chronic administration of antiarrythmic drugs.

    • Cardiac assisted devices - may be indicated if severe depression of LV function or if concerned for rapid deterioration.

  • After PPCM, future pregnancy: 

    • Avoid future pregnancy if EF fails to improve, as mortality increases up to 50% if EF does not improve!

Pelvimetry

/

What is pelvimetry? 

  • Measurement of the female pelvis that has theoretically been used to try and identify cephalo-pelvic disproportion.

  • Originally described by Dr. Caldwell and Dr. Moloy in “Anatomical Variations in the Female Pelvis: Their classification and Obstetrical Significance” in 1938.

  • Clinical evidence shows, however, that all pregnant women should be allowed a trial of labor regardless of pelvimetry results!

    • Cochrane review in 2017 that looked at deciding mode of delivery for cephalic fetuses at term:

      • X-ray pelvimetry vs. no pelvimetry or clinical pelvimetry was the only comparison used due to lack of trials identified that used other types of pelvimetry.

      • There was not enough evidence to support use of X-ray pelvimetry for deciding mode of delivery.

      • Women who underwent X-ray pelvimetry were more likely to have C-section, but there was no clear difference in perinatal outcomes in these groups.

    • Even the WHO in Feb 2018 stated that routine clinical pelvimetry may increase cesarean section without clear benefit for birth outcomes

  • Ok… so why are we even talking about pelvimetry? 

    • Historical purposes so that you know what people are talking about.

      • CREOGs sometimes test on the different measurements of the pelvis used! 

What are the traditional types of pelvises? 

  • Gynecoid - round to slightly oval inlet 

    • Traditionally the pelvis that is most likely in women; most “favorable” for SVD.

  • Android - triangular inlet, and prominent ischial spines, with more angulated pubic arch

    • Thought to lead to longer labor or cephalo-pelvic disproportion.

  • Anthropoid - the widest transverse diameter is less than the anteroposterior (obstetrical) diameter.

    • Traditionally thought to lead to more OP babies 

  • Platypelloid - Flat inlet with shortened obstetrical diameter. Wide or transverse oval appearance “kidney shaped.” 

    • Traditionally thought to be difficult for vaginal birth 

But remember! Clinical evidence shows that a trial of vaginal birth should be done for all women regardless of pelvimetry

What are the various measurements for pelvimetry?

Pelvic Inlet 

  • Transverse diameter of the pelvic inlet 

    • Measure the distance between the iliopectineal lines at the widest transverse distance (usually 13-14.5cm).

  • Obstetric conjugate 

    • Line between the closes bony points of the sacral promontory and the pubic bone next to the symphysis (normally 10-12 cm).

  • Interspinous distance 

    • The line between the closest bone points of the ischial spines (9.5-11.5cm) 

Pelvic outlet 

  • Sagittal pelvic outlet diameter aka obstetric AP diameter of the pelvic outlet 

    • Closest bony points of the sacrococcygeal joint and the pubic bone next to the symphysis (normally 9.5-11.5cm) 

  • Intertuberous diameter 

    • Closest bony points of the ischial tuberosities (normally 10-12 cm)

The Surgical Abdomen in Pregnancy

/

A “surgical” or “acute abdomen” is a serious acute intra-abdominal condition accompanied by pain, tenderness, and muscular rigidity, for which emergency surgery should be contemplated.

This can be complicated by pregnancy because there are many physiologic and anatomic changes in pregnancy that can sometimes change the presentation of what we usually associate with acute abdomen 

Anatomic and physiologic changes in pregnancy

  • Enlarging uterus 

    1. Uterus becomes intra-abdominal organ instead of pelvic organ at 12 weeks.

    2. Can increase from 70g → 1110g and hold up to 5 L volume.

    3. Uterus can compress ureters → can look like hydronephrosis and mimic urolithiasis.

    4. Will displace other abdominal organs (mostly the viscera):

  •  A relaxed and stretched abdominal wall can mask guarding.

  • Additional physiologic changes: 

    • GI: 

      • Delayed emptying of stomach, relaxed lower esophageal sphincter (remember: blame progesterone for everything!) → increase nausea/vomiting, bloating, GERD

      • Also decreased GI transit (slower motility d/t relaxed GI smooth muscles, again d/t progesterone) → Constipation 

        • Nausea and/or constipation with associated symptoms can confound clinical gestalt when evaluating acute abdomen.

    • Heme:

      • Leukocytosis -standard in pregnancy, though can give impression of infection.  

Recognizing the Acute Abdomen in Pregnancy 

  • If someone comes with acute abdomen signs, you should treat them as if they have an acute abdomen until proven otherwise:

    • Abdominal rigidity, rebound, tenderness, guarding 

  • Causes of acute abdomen in pregnancy:

Some clinical pearls for more common causes of acute abdomen in pregnancy: 

  • Appendicitis: Classically taught that the appendix is displaced in pregnancy, BUT RLQ pain is still the most common symptom. Fever might be present in some patients.

    • Ultrasound has sensitivity of 67-100% and specificity of 83-96% in pregnancy (first line imaging).

    • CT has sensitivity of 86% and specificity of 97% - usually not used as much due to concerns for radiation.

    • MRI has high sensitivity and specificity - generally 2nd line, if if ultrasound is inconclusive.

    • Treatment: SURGERY! 

  • Cholecystitis: Murphy’s sign is still typically positive.

    • Ultrasound is the investigation of choice with sensitivity >95%.

    • Treatment: 

      • Admission, make NPO, give antibiotics.

      • Symptoms of cholecystitis may abate within 7-10 days of starting nonoperative treatment, but there is high risk of recurrence or serious complication.

      • In first and second trimester → good surgical candidates should undergo cholecystectomy.

      • In third trimester Nonoperative medical management with abx and fluid therapy should be tried first to allow delay of choley until postpartum, owing to technical difficulty in performing at this gestational age.

      • Remember, this is ONLY if it’s uncomplicated. If there is any sign of sepsis, perforation, or disease progression on antibiotics → immediate surgery.

A Word on Imaging 

  • Recall our prior episode on imaging in pregnancy! The quick version:

    • Try ultrasound first for acute abdomen. Usually has high sensitivity and specificity, but the efficacy can decline after 32 weeks of gestation because of technical difficulties due to enlarging uterus 

    • Next is MRI, generally.

    • For ionizing radiation:

      • Risk of radiation exposure on a developing fetus depends on both the dose of radiation and gestational age at which exposure occurs.

      • Fetal mortality is most significant in the first 2 weeks of conception (3-4 weeks pregnant).

      • Most vulnerable period for teratogenicity is during organ development (usually up to 12 weeks).

      • Risk of ionizing radiation-induced fetal harm is negligible at 50 mGy or less and risk of malformation increases only slightly with doses >150mGy.

        • Usual dose of CT abdomen/pelvis is about 25 mGy, and can be reduced to 13 mGy with automated exposure control facility in modern CT scanners.

A Word on Mode of Surgery 

  • We are not general surgeons! 

  • However, multiple studies show that laparoscopic surgery is less invasive and is feasible and safe in select pregnant patients.

  • If you can time surgery, the best time is 2nd trimester or very early 3rd tri 

    • Pregnancy itself does not increase postoperative morbidity in pregnant women compared to nonpregnant women.

    • Timing works due to decreased exposure of fetus to anesthetic agents during organogenesis and decreased risk of SAB compared to 1st trimester.

    • In second trimester, uterus is not so big that it is hard to work around.

  • Obstetricians should be able to counsel/provide for intraoperative or peri-operative fetal monitoring if indicated and feasible — generally pre/post doptones pre-viability, and a discussion about continuous monitoring if after viability.

  • Postoperative care considerations:

    • If viable fetus, there should be additional monitoring of fetal heart rate and uterine activity post operatively.

    • If not viable, there should be dop tones obtained both before and after surgery 

    • For post-op pain, usual post-op care is usually permissible.

      • Avoid NSAIDs if possible after 32 weeks due to concern for premature closure of the fetal ductus arteriosis.

Second Trimester Abortion

/

Second Trimester Abortion: Legal Issues

  • In the US, 1.2 million abortions occured in 2008.

    • Of these, approximately 10% took place after 13 weeks, with more than half occurring between 13 and 15 weeks. 

    • Only 1.3% of abortions are performed at or after 21 weeks gestation.

  • There are varying state-level statutes that may limit the gestational age for obtaining an abortion, or the type of abortion treatment that can be offered.

  • The Guttmacher Institute maintains an overview of abortion laws by state. Some highlights from them:

    • 43 states have gestational age limits on when abortion can be performed. These range from 20 weeks to viability, with some statutes currently being challenged in court that could restrict access as early as 6-15 weeks.

    • 21 states prohibit “partial-birth” abortions, which is a misnomer that we will explain momentarily.

      • 2 states have standing bans on standard dilation and evacuation (Mississippi and West Virginia), with an additional 9 having some enjoinment on enforcement of a ban on D&E. 

    • 26 states require waiting periods between counseling and a procedure. 18 states require specific counseling which may include false or misleading information on:

      • Link between breast cancer and abortion (5 states).

      • The ability of a fetus to feel pain (13 states).

      • Long-term mental health consequences of abortion (8 states).

Methods of 2nd Trimester Abortion

Dilation and Evacuation

  • Use of medication or mechanical techniques to dilate the cervix, followed by the use of grasping forceps to remove the fetus.

  • Most commonly achieved with osmotic dilators in combination with misoprostol for cervical ripening.

    • The success of cervical preparation at 18 weeks gestation and above may be improved with the use of mifepristone the night prior to the procedure in combination with osmotic dilators.

      • However mifepristone may also increase risk of pregnancy expulsion prior to the procedure, particularly if misoprostol is subsequently used for further dilation.

  • A variant of this technique is known by a variety of names such as “dilation and extraction” or “intact D&E,” in which further dilation is achieved which allows for removal of an intact fetus except for possible calvarial decompression. 

    • This has been labeled in some publications as partial-birth abortion and may be restricted to some degree in a number of jurisdictions. 

    • In order to avoid consequences associated with these laws, some experts advise preoperative feticidal injection with KCl or digoxin. 

Medical or Induction Abortion

  • Induction may also be used to achieve abortion, however this is less-cost effective, takes more time, and is more associated with complications.

  • Generally, this is achieved through similar techniques for cervical ripening to labor induction -- mechanical dilators or balloon catheters, misoprostol, and oxytocin. 

    • The most efficacious medical management is mifepristone administered 24-48 hours prior to misoprostol initiation, based on RCT evidence.

    • Osmotic dilators do not necessarily add benefit to misoprostol in this setting. 

  • Preoperative feticidal injection does not shorten the duration of induction, but may be used if preferable to the woman or provider to avoid transient fetal survival after expulsion. 

  • ACOG lists three primary techniques for medication abortion in the second trimester; ACOG and SFP note that the mife-miso regimen is the most efficacious for 2nd trimester induction abortion:

Hysterotomy or Hysterectomy

  • Abdominal surgery is rarely indicated for second-trimester abortion, but is occasionally indicated in the event other procedures fail or are contraindicated. 

  • A prior cesarean or uterine scar is not an indication for hysterotomy for abortion, or for the avoidance of misoprostol, at least up until about 28 weeks gestation.

    • Retrospective cohort studies have demonstrated an insignificantly increased risk of uterine rupture for women with one prior cesarean delivery around 0.28%, versus rupture risk for unscarred uteri around 0.04%.

      • There is insufficient data to guide management on women with 2+ CDs. 

    • However, this remains well below the established acceptable risk threshold with trial of labor after cesarean at term without misoprostol use (rupture risk for 1 prior CD at 0.5-0.7%). 

      • The risk of rupture is suspected to increase with misoprostol use at or after 28 weeks, based on TOLAC data.

Complications and Other Situations

  • Mortality is 0.6 / 100k legal, induced abortions, with that rate being tied to gestational age at the time of abortion.

    • At 21 weeks gestation or greater, the rate of mortality rises to 8.9 / 100k procedures.

    • Maternal mortality for live birth is 17.6 / 100k live births in USA (or double that for 21+wk abortion, by comparison).

  • Postabortion hemorrhage is defined as “blood loss > 500cc and/or bleeding requiring a clinical response such as transfusion or hospital admission.”

    • Rates of transfusion range from 0.1 - 0.7%, with higher rates seen for medical 2nd trimester abortion. 

    • Management is similar to hemorrhage after term vaginal delivery, ruling out retained products and uterine atony as primary causes.

      • Cervical laceration, uterine rupture, and abnormal placentation are also rarer but important concerns, particularly in more advanced gestational age and in women with prior cesarean delivery. 

  • Postabortion infection is uncommon, occurring in 0.1-4% of 2nd trimester abortions.

    • Antibiotic prophylaxis is indicated prior to dilation and evacuation.

      • SFP recommends 200mg doxycycline preoperatively.

      • The ACOG PB recommends use of 100mg doxycycline preoperatively and 200mg postoperatively

      • RCT methodologies on antibiotic use support solely preoperative antibiotic use as sufficient. 

  • Postabortion contraception placement in the form of IUDs additionally does not increase infection risk, but expulsion rates may be higher after abortion than with interval placement.

  • Reversible contraception of almost any kind (no diaphragms or cervical caps) can be initiated immediately post-abortion, and ovulation can resume as soon as 21 days post-procedure.

Cardiovascular Disease in Pregnancy Part II: Classifications and Valvular Disease

/

There are multiple systems for the classification of cardiac disease in pregnancy:

  • Modified WHO Pregnancy Risk Classification - this scale is based on the presumptive risk of cardiac disease towards pregnancy outcomes.

    • Class I: no detectable increase in maternal mortality, and no or only mild increase in morbidity.

      • Ex: uncomplicated/small/mild pulmonary stenosis, PDA, mitral valve prolapse; successfully repaired simple lesions (PDA or septal defects); isolated atrial or ventricular ectopic beats

    • Class II: small increased risk in maternal mortality, moderate increase in morbidity.

      • Ex: unoperated ASD or VSD; repaired tetralogy of Fallot; most arrhythmias.

    • Class III: significantly increased risk of maternal mortality or severe morbidity. Recommended intensive specialist cardiac and obstetric monitoring throughout pregnancy, delivery, and postpartum.

      • Ex: mechanical valve, systemic right ventricle, Fontan circulation, unrepaired cyanotic heart disease, aortic root dilation 40-45mm in Marfan patient or 45-50mm in bicuspid valvular disease.

      • Some patients may fall into an in between II-III category (i.e.,m mild LV impairment, HCM, Marfan syndrome without root dilation).

    • Class IV: extremely high risk of maternal mortality or severe morbidity; pregnancy considered contraindicated with recommendation for termination if pregnancy occurs. If continues, manage with specialist involvement as per class III.

      • Ex: pulmonary arterial hypertension, severe systemic ventricular dysfunction (LVEF < 30%), previous peripartum cardiomyopathy with any residual LV dysfunction, severe mitral or aortic stenosis; aortic root dilation in Marfan syndrome > 45mm or >50mm in bicuspid disease; native severe aortic coarctation.

  • NYHA Functional Classification - likely a familiar scale, based off of cardiac disease symptoms and functional status.

    1. Class I - cardiac disease, but no symptoms and no limitations in ordinary physical activity 

    2. Class II - mild symptoms and slight limitations during ordinary activity

    3. Class III - significant limitation in activity due to symptoms. Comfortable at rest 

    4. Class IV - severe limitations. Symptoms even while at rest.  

  • CARPREG II or ZAHARA - point-based scales for risk prediction for a significant cardiac event in pregnancy:

Valvular Disease

  • Native Valvular Disease

    • Stenosis - the valve is narrowed or stiffened and does not allow for passage of blood.

      • Tricuspid stenosis - makes it hard for blood to pass from the right atrium into the right ventricle.

        • With increased cardiac output as well as increased systemic volume, stenosis of the tricuspid valve can lead to systemic overload (ie. swelling, JVD, etc); severe stenosis can make it so that less blood gets into the pulmonary system.

      • Pulmonic stenosis - blood is impaired in passage from RV to lungs.

        • In isolation, this is generally well tolerated since pregnancy provides additional volume, thus providing more blood to pump to the lungs in totality.

        • However, can be associated with other complex heart disease, in which outcomes are not as good.

      • Mitral stenosis - blood flow challenged from LA to LV.

        • Most common cause worldwide: rheumatic heart disease.

        • Increased CO and HR leads to decreased filling (diastolic) time. This promotes increased left atrial pressure and dilation, leading to atrial fibrillation, pulmonary edema.

        • Maternal mortality with severe MS is 3%.

        • Treatment in pregnancy is with beta blockers to decrease HR and increase filling time. Anticoagulation needed if atrial fibrillation develops.

      • Aortic stenosis - blood flow impaired from LV to aorta.

        • Most common cause: bicuspid aorta (congenital).

        • Pregnancy well tolerated except for patients with severe disease; need good flow systemically to accommodate increased cardiac output and stroke volume demand of pregnancy.

        • Severe AS can result in heart failure, arrhythmias, and pulmonary edema.

    • Regurgitation - insufficiency across a valve, allowing for backflow of blood.

      • Tricuspid regurgitation: overall well-tolerated, but higher risk of right-sided failure and atrial arrhythmia.

      • Pulmonic regurgitation: moderate or severe cases may lead to RV failure and arrhythmia.

      • Mitral regurgitation: usually well tolerated as long as there is absence of LV systolic dysfunction or pulmonary hypertension.

        • If severe, ideally valve is repaired or replaced prior to pregnancy.

      • Aortic regurgitation: also well-tolerated overall, unless signifiant baseline symptoms.

        • Risk of heart failure due to volume overload; can also occur alongside LV systolic dysfunction, severe LV dilation, or pulmonary hypertension.

  • Mechanical or Prosthetic Valves

    • There is an increased risk of thrombosis/VTE in pregnancy, and these patients will need to be on anticoagulation.

    • Warfarin is the preferred anticoagulant despite risk of embryopathy, as the risk of thrombus is higher on heparin or heparin-like agents.

Pearls on managing valvular disease in various stages of pregnancy:

  • Prepregnancy 

    • Depending on severity, may need have preconception counseling with cardiologist and MFM.

    • Patients with severe mitral and aortic stenosis may need balloon valvuloplasty beforehand.

  • During pregnancy 

    • Really, this is based on their cardiovascular risk score (ie. WHO classification) 

    • Most of these patients will need an echocardiogram during early pregnancy, and likely follow up at an interval depending on hemodynamic tolerance.

    • Evaluate and treat any symptoms of heart failure!

    • Labor and delivery: vaginal delivery is usually the preferred method of delivery unless: 

      • Mitral stenosis with NYHA class III/IV or have pulmonary hypertension 

      • Severe, symptomatic AS 

    • Especially with more severe symptoms, consider early epidural (especially in mitral stenosis) and assisted second stage.

    • Telemetry if risk for arrythmia exists.

  • After delivery 

    • For many of these lesions, need to reevaluate an echocardiogram.

    • Many of these patients, due to fluid shifts, are at higher risk for arrhythmias and heart failure after delivery.

    • Strict I/Os in the postpartum period!

    • Consider telemetry if risk for arrhythmia.