Cardiovascular disease in pregnancy: does it give you sleepless nights?

May 4, 2017 Posted by Dr. Duncan Hogg no Comment

Even experienced general cardiologists find cardiovascular disease in pregnancy can give you sleepless nights. Most of the time we simply need to reassure, but a small percentage of cases need intense support, often with a complex clinical path. A good outcome is not guaranteed, which as always in young previously healthy individuals, raises your anxiety.    

I’ve been involved in a broad range of challenging cases of cardiovascular disease in pregnancy. I’d rather not see another partially thrombosed mechanical mitral valve in a pregnant woman; thankfully she survived, and quite remarkably had another child without complication to term. And I was recently discussing the optimal out-patient management after a few interesting cases.  

In response to these, I revisited the ESC guidance of 2011, and the very impressive MBRACE-UK maternal mortality report from December 2016. The latter is a fantastically thorough and detailed document. It’s robust analyses into maternal deaths leads to strongly evidenced and clear messages for the whole community who may be involved in the care of pregnant women.

Murmurs

A case with an unexpected finding interested me in our practice around murmurs in pregnancy. Receiving a referral for murmur in pregnancy I followed my routine and booked an urgent echo, although I can’t remember the last time I picked up important occult pathology this way.

We know pregnancy is a physiological stress test, and previously undiagnosed abnormalities can declare themselves when the haemodynamic changes are settled in the second trimester. But, over 90% of pregnant women will have an ejection systolic murmur starting between 12-20 weeks and continuing through pregnancy. You’d expect a cardiologist to be better at defining a murmur associated with significant valve disease but, an echo is simple and reliable.

I asked if my colleagues if they took a history and/or listened themselves before echoing in this setting, and most didn’t. One mentioned he listens first but conceded that even if he thought it was a benign flow murmur he would still do an echo, for both the patients and obstetrics teams’ reassurance.  What do you do if convinced a benign murmur, not echo or review again later?

The echo found a bicuspid aortic valve, with no stenosis or regurgitation, and no coarctation, but of clear concern was the dilated aortic root of 43mm. There was no family history of BAV, aortic dissection, or sudden cardiac death. We discussed the finding and the need for increased surveillance, and thankfully the dimensions didn’t change and there was no adverse event.

The maternal mortality report states that 8.5 women die per 100,000 maternities in the UK, and 2 per 100,000 are from heart disease, making it the commonest cause of maternal death overall.  77% of cases were not known to have pre-existing cardiac problems, although the breakdown shows many are unlikely to be diagnosed before they clinically declare themselves.  

Sudden arrhythmic death in morphologically normal hearts (SAD/MNH) 31%; ischaemic 22%; cardiomyopathy 18%; aortic dissection 14%; ACHD 7%; valvular disease 7%; systemic hypertension 4%;  and others 5%.

Valvular heart disease

In the 2009-14 reporting period, 11 women died from valvular heart disease. Two women had severe rheumatic mitral valve disease; two died from endocarditis on native valves (one aortic, one tricuspid); the other 7 had mechanical prosthetic valves and died from valve dysfunction (n=2), valve thrombosis (n=4) and a CVE (n=1). Three of the prosthetic valves were in the mitral position and four in the aortic position.

I had an intriguing exception with a South Asian nursing colleague who I saw with palpitations a little while after the birth of her first child. Her echo revealed she had severe mitral stenosis, and yet she’d had no trouble at all in her first pregnancy, she hadn’t been referred for her murmur! After a successful balloon valvotomy, she had her second child, with another untroubled pregnancy.  Remarkable.

Known CV disease

Those with known CV diagnoses can be a little easier as they more likely will have been counselled on the risks of pregnancy, and an agreed plan can be put into place with the teams involved, including contingencies if problems arise. But this isn’t always the case, as I found in one of the more complex out-patients I’ve been involved with.  

I received an urgent call from a GPwSI in Obstetrics on one the Scottish northern isles with significant concerns about how things should move forward in women with very severe, nearly critical, aortic stenosis due to a congenital bicuspid valve, who was now 8/9 weeks pregnant. She had not followed through with work-up and surgical referral a year before, and not been going to ACHD follow-up. Being from Eastern Europe with modest English language skills had probably lead to some difficulties in counselling her about the true risks of becoming pregnant.

The high mortality in this group was appreciated, and she was transferred urgently. A detailed assessment, long discussions with the patient and partner, and the ACHD surgical centre followed. Sadly she lost this pregnancy, but with more robust contraception in place, and plans to have urgent surgery with a bioprosthetic valve, I hope her future path can be less fraught.      

Increased survelliance

The ACHD team with their strong network of inter-service collaboration was essential in this case. Illustrating one of the major themes of both the ESC and MBRACE-UK documents, of having a close network of senior doctors in each service in regular contact to aid patient care.  

Following our group discussion, I was then chatting to a colleague who was reviewing an echo and about to go to the maternity unit. He was seeing a pregnant woman who was diabetic, who’d had a previous MI with mild LVSD, and was getting increased surveillance as result. This nicely illustrates why ischaemic heart disease is the second largest group for causing mortality.

Risk factors

The confidential mortality report found almost half of the women who died were overweight or obese. The risk of cardiac death increased with increase in age and was twice as high in women aged 35–39 years, and nearly four times higher in women 40 years or older. 26% of women who died smoked. Nearly half of the ischaemic heart disease deaths were from atherosclerotic disease. It seems clear there is a case for doing conventional CV risk stratification in pregnant women now.   

Finally, I was also looking to better define the utility of heart rhythm monitoring in this setting, suspicious it was giving false reassurance especially for life-threatening arrhythmias.

Palpitations

A case of my colleagues of a woman referred for palpitations in the mid-trimester of pregnancy, reasonably caused significant concern, especially in our obstetric service. She had a normal resting ECG, Holter, and echo, and still had a clinic appointment in place despite the normal tests. Tragically she died the week before she was due to be seen. The post mortem showed a structurally normal heart. Could this have been avoided? Were the palpitations evidence of the occult pathology, or simply that experienced by the majority, if not all, pregnant women?  

In the SADS/MNH case reviews in the confidential mortality report there were few prodromal indications reported; one woman, who died three months postpartum, had a father with long QT syndrome; another woman was documented to have had previous blackouts. Therefore, even a detailed cardiology history would be unlikely to pick up a subtlety that would have changed management and the sad final outcomes in these cases.

But, as with all those who die from SAD/MNH, there should be a routine of a molecular post mortem as there is a real possibility of identifying an inherited channelopathy, with the potential of preventing future sudden deaths amongst relatives. Our local forensic pathologist reviews all cases of SCDs with clinical genetics and one of our EP docs, who together run the familial arrhythmia clinic, which is a very strong collaboration and I think increasingly usual.  

The verdict

So, am I still going to echo all pregnant women referred with murmurs for the remote possibility of finding significant valve disease or an important incidental finding, and for the reassurance of all, probably yes. Will I continue to do rhythm monitoring, along with a resting ECGs, for palpitations in pregnancy, probably yes too. Should we have stronger links and a formal framework with the obstetric service, definitely. Am I still going to get some sleepless nights over pregnant women with known cardiovascular disease, I’m afraid so!

This Blog is Posted by Dr. Duncan Hogg

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