My patient with aortic sclerosis has a loud systolic ejection murmur. What is the exact mechanism of this murmur?

We usually blame cardiac murmurs on the “turbulence” caused by blood flowing past an irregular valve surface but, believe it or not, how the murmur is created has been a matter of controversy. 1-4

For sure, murmurs are generated by disturbance of laminar blood flow (ie, turbulence) but over the years many have argued that turbulence per se fails to produce adequate acoustic force to be audible at the chest wall.2 Although challenged by some,1  the concept of “vortex shedding” borrowed from fluid dynamics is fascinating and has been proposed as a potential explanation.

Per this theory, just as a boulder causes a stream to separate and generate vortices, valves (particularly when abnormal) also create vortices. As the vortices are shed near the valve, they leave in their place relatively calm wakes which are then rapidly filled by flowing blood, creating the sound of a murmur.  

Two important variables in this theory are velocity and viscosity. When the velocity of blood flow increases substantially as in high cardiac output states (eg, fever, pregnancy), vortex shedding and the intensity of the murmur also increase. Similar phenomenon may be expected when the blood viscosity is lowered (eg, in anemia).

 

References

  1. Sabbah HN, Stein PD. Turbulent blood flow in humans: Its primary role in the production of ejection murmurs. Circ Res 1976;38: 513-24. https://www.ncbi.nlm.nih.gov/pubmed/1269101
  2. Alpert MA, Systolic murmurs. In Walker HK, Hall WD, Hurst JW. Clinical methods: The history, physical, and laboratory examinations. 3rd ed. Butterworths, Boston, 1990. https://www.ncbi.nlm.nih.gov/books/NBK345/
  3. Bruns D. A general theory of the causes of murmurs in the cardiovascular system. Am J Med 1959;27:360-74. http://www.amjmed.com/article/0002-9343(59)90002-6/fulltext
  4. Guntheroth WG. Innocent murmurs: A suspect diagnosis in non-pregnant adults. Am J Cardiol 2009;104:735-7. https://www.ncbi.nlm.nih.gov/pubmed/19699354
My patient with aortic sclerosis has a loud systolic ejection murmur. What is the exact mechanism of this murmur?

My elderly patient developed a new left bundle branch block following transcatheter aortic valve replacement. Is this a frequent occurrence?

Yes, conduction abnormalities, particularly left bundle branch block (LBBB), frequently complicate transcatheter aortic valve replacement (TAVR).

A 2016 systematic review and meta-analysis reported new-onset LBBB following TAVR and persisting at hospital discharge in 13.3%-37% of patients1; the incidence may be higher or lower depending on the type of prosthesis used.2,3 In the same systematic review, new-onset LBBB was associated with a higher risk of permanent pacemaker placement (PPI) and cardiac death during 1-year followup.   In another study, persistence of LBBB post-TAVR without PPM placement was associated with an increased risk of syncope, complete AV node block, and PPI, but not overall mortality.4

The underlying anatomy of the conduction system may help explain post-TAVR conduction complications. The AV node is located adjacent to the membranous septum, closely associated with the subaortic region and LV outflow track, giving rise to the LBB.5 Protrusion of TAVR prostheses into the LV outflow tract, the mechanical injury occurring during the predilation or the positioning of the valve, and potential trauma to the conduction system by the catheters and guidewires used in TAVR may all contribute to these complications.3,5

References

  1. Regueiro A, Altisent OA, Del Trigo M, et al. Impact of new-onset left bundle branch block and periprocedural permanent pacemaker implanation on clinical outomces in patients undergoing transcatheter aortic valve replacement: A systematic review and meta-analysis. Circ Cardiovasc Interv 2016;9:e003635. http://circinterventions.ahajournals.org/content/9/5/e003635.long
  2. Nazif, T.M., Williams, M.R., Hahn, R.T., Kapadia, S., Babaliaros, V. et al. Clinical implications of new-onset left bundle branch block after transcatheter aortic valve replacement: analysis of the PARTNER experience. Eur. Heart J. 2014;21:1599-1607. https://www.ncbi.nlm.nih.gov/pubmed/24179072
  3. Bourantas CV, Serruys PW. Evolution of transcatheter aortic valve replacement. Circ Res 2014;114:1037-1051. http://circres.ahajournals.org/content/114/6/1037
  4. Urena, M., Mok, M., Serra, V., Dumont, E., Nombela-Franco, L. et al. Predictive factors and long-term clinical consequences of persistent left bundle branch block following transcatheter aortic valve implantation with a balloon-expandable valve. J Am Coll Cardiol. 2012;60:1743-1752. https://www.ncbi.nlm.nih.gov/pubmed/23040577
  5. Piazza, N., Jaegere, P., Schultz, C., Becker, A.E., Serruys, P.W., Anderson, R.H. Anatomy of the aortic valve complex and its implications for transcatheter implantation of the aortic valve. Circ Cardiovasc Interv. 2008;1:74-81. https://www.ncbi.nlm.nih.gov/pubmed/20031657

Contributed by Salvatore D’Amato MD, Mass General Hospital, Boston, MA

My elderly patient developed a new left bundle branch block following transcatheter aortic valve replacement. Is this a frequent occurrence?

In my patient on oral anticoagulation about to undergo coronary stenting, will triple therapy (an oral anticoagulant plus two antiplatelet agents) be necessary or can I get away with double therapy (an oral anticoagulant plus a single antiplatelet agent)?

 

Patients with atrial fibrillation (AF) who need percutaneous coronary intervention (PCI) after acute coronary syndrome or for stable angina pose a treatment challenge as oral anticoagulants (OACs) and dual antiplatelet therapy (DAPT) are often used concurrently to decrease the risk of systemic thromboembolism and stent thrombosis. However, “triple therapy”, including aspirin, a P2Y12 inhibitor, and an OAC (eg, warfarin or a direct oral anticoagulant-DOAC), also increases the risk of bleeding, necessitating several recent landmark trials to better address the subject.

Two modest-sized RCTs (WOEST and ISAR-TRIPLE) reported that when compared to triple therapy (DAPT plus warfarin), double therapy (single antiplatelet agent plus INR-targeted warfarin) is associated with reduced risk of bleeding complications without an increased risk of thrombotic events. 1,2

Two larger RCTs, PIONEER AF-PCI and RE-DUAL PCI, studied rivaroxaban and dabigatran, respectively, in patients with non-valvular AF undergoing PCI and found a reduction in bleeding events in patients receiving double therapy (single antiplatelet agent plus DOAC) compared to triple therapy (DAPT plus warfarin), without an increased risk of thrombotic complications. 3,4

Collectively, these studies suggest that it may be safe to treat patients with increased risk of bleeding with double therapy (even immediately following PCI) without an increase in thrombotic events. If triple therapy is elected, duration should be minimized, clopidogrel should be preferred over more potent P2Y12 inhibitors, and a PPI should be considered.

 

References:

  1. Dewilde WJ, Oirbans T, Verheugt FW, et al. Use of clopidogrel with or without aspirin in patients taking oral anticoagulant therapy and undergoing percutaneous coronary intervention: an open-label, randomised, controlled trial. Lancet. 2013;381:1107-15. https://www.ncbi.nlm.nih.gov/pubmed/23415013
  2. Fiedler KA, Maeng M, Mehilli J, et al. Duration of triple therapy in patients requiring oral anticoagulation after drug-eluting stent Implantation: The ISAR-TRIPLE Trial. J Am Coll Cardiol. 2015;65:1619-29. https://www.ncbi.nlm.nih.gov/pubmed/25908066
  3. Gibson CM, Mehran R, Bode C, et al. Prevention of bleeding in patients with atrial fibrillation undergoing PCI. N Engl J Med. 2016;375:2423-2434. http://www.nejm.org/doi/pdf/10.1056/NEJMoa1611594
  4. Cannon CP, Bhatt DL, Oldgren J, et al. Dual antithrombotic therapy with dabigatran after PCI in atrial fibrillation. N Engl J Med. Published online, Aug, 27, 2017. http://www.nejm.org/doi/pdf/10.1056/NEJMoa1708454

 

Contributed by Amulya Nagarur, MD, Mass General Hospital, Boston, MA

In my patient on oral anticoagulation about to undergo coronary stenting, will triple therapy (an oral anticoagulant plus two antiplatelet agents) be necessary or can I get away with double therapy (an oral anticoagulant plus a single antiplatelet agent)?

Do most patients with mycotic aneurysms have endocarditis?

No! In fact, the great majority of patients who develop mycotic aneurysm (MAs) in the postantibiotic era have no evidence of endocarditis1-3.

MAs are thought to be related to microbial arteritis due to blood stream infection of any source with implantation of circulating pathogen (usually bacterial) in atherosclerotic, diseased, or traumatized aortic intima. Plus, MAs may develop due to an adjacent infectious process (eg, vertebral osteomyelitis), either through direct extension or via lymphatic vessels, pathogen seeding of vasa vasorum, or infection of a pre-existing aneurysm1,2.  All these factors may occur in the absence of endocarditis.

Many of your patients may be at risk of MA such as those with advanced age or history of diagnostic or therapeutic arterial catheterization, illicit intravascular drug use, hemodialysis and depressed host immunity1-3..  Staphylococcus aureus, Salmonella sp, S. epidermidis and Streptococcus sp are common culprits in descending order1-3.

So think of MA in your patient with recent blood stream infection,  particularly due to S. aureus or Salmonella sp, in the setting of persistent signs of infection  with or without evidence of endocarditis.

Final Fun Fact: Did you know that the term “mycotic aneurysm” is a misnomer, having been first introduced by Sir William Osler to describe aneurysms of the aortic arch in a patient with (you guessed it) bacterial not fungal endocarditis?

References:

  1. Gomes MN, Choyke PL, Wallace RB. Infected aortic aneurysms: A changing entity. Ann Surg 1992;215:435-42. https://www.ncbi.nlm.nih.gov/pubmed/1616380
  2. Muller BT, Wegener OR, Grabitz K, et al. Mycotic aneurysms of the thoracic and abdominal aorta and iliac arteries: Experience with anatomic and extra-anatomic repair in 33 cases. J Vasc Surg 2001;33:106-13. https://www.ncbi.nlm.nih.gov/pubmed/11137930
  3. Mukherjee JT, Nautiyal A, Labib SB. Mycotic aneurysms of the ascending aorta. Tex Heart Inst J 2012;39:692-5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3461658/
Do most patients with mycotic aneurysms have endocarditis?

Does methotrexate reduce the risk of cardiovascular events in patients with rheumatoid arthritis?

The weight of the evidence suggests that methotrexate reduces the overall risk of cardiovascular events (CVEs)—including myocardial infarction, congestive heart failure, stroke, and or major adverse cardiac events—in RA patients (RR 0.72, 95% CI 0.57-0.91)1.

Aside from its effect on controlling systemic inflammation, methotrexate has also been shown to increase HDL and reduce total cholesterol/HDL ratio in patients with RA compared with treated non-RA controls2. In vitro, methotrexate appears to activate mechanisms involved in reverse transport of cholesterol out of the cell to the circulation for eventual excretion3. Not surprisingly then, methotrexate has also been reported to decrease atherosclerotic plaque burden measured by carotid artery intima-media thickness2.

We tend to think of RA as a disease that primarily causes arthritis but its effects may extend far beyond the joints. Patients with RA have an increased risk of cardiovascular deaths compared to the general population4, likely due to a variety of factors, including accelerated atherosclerosis secondary to chronic inflammation. At baseline, RA patients also have an unfavorable lipid profile with decreased HDL and higher total cholesterol/HDL ratio.

Fun Final Fact: Did you know that methotrexate is on the WHO Model List of Essential Medicines (April 2015) not only as a cancer drug but for treatment of RA as well5?

References:

  1. Roubille C, Richer V, Starnino T, McCourt C, McFarlane A, Fleming P, Siu S, Kraft J, Lynde C, Pope J, Gulliver W, Keeling S, Dutz J, Bessette L, Bissonnette R, Haraoui B. The effects of tumour necrosis factor inhibitors, methotrexate, non-steroidal anti-inflammatory drugs and corticosteroids on cardiovascular events in rheumatoid arthritis, psoriasis and psoriatic arthritis: a systematic review and meta-analysis. Ann Rheum Dis. 2015;74:480-9. https://www.ncbi.nlm.nih.gov/pubmed/25561362
  2. Georgiadis AN, Voulgari PV, Argyropoulou MI, Alamanos Y, Elisaf M, Tselepis AD, Drosos AA. Early treatment reduces the cardiovascular risk factors in newly diagnosed rheumatoid arthritis patients. Semin Arthritis Rheum 2008;38:13-9. https://www.ncbi.nlm.nih.gov/pubmed/18191989
  3. Reiss AB, Carsons SE, Anwar K, Rao S, Edelman SD, Zhang H, Fernandez P, Cronstein BN, Chan ES. Atheroprotective effects of methotrexate on reverse cholesterol transport proteins and foam cell transformation in human THP-1 monocyte/macrophages. Arthritis Rheum 2008;58:3675-83. https://www.ncbi.nlm.nih.gov/pubmed/19035488
  4. Aviña-Zubieta JA, Choi HK, Sadatsafavi M, Etminan M, Esdaile JM, Lacaille D. Risk of cardiovascular mortality in patients with rheumatoid arthritis: a meta-analysis of observational studies. Arthritis Rheum 2008; 59:1690-7. https://www.ncbi.nlm.nih.gov/pubmed/19035419
  5. WHO Model List of Essential Medicines (April 2015). http://www.who.int/medicines/publications/essentialmedicines/en/

 

Contributed by Brian Li, Medical Student, Harvard Medical School

Does methotrexate reduce the risk of cardiovascular events in patients with rheumatoid arthritis?

Does hypertension cause epistaxis?

Although traditionally we think of epistaxis as a potential sign of hypertension, particularly when severe, whether hypertension causes epistaxis is unclear and even the association of these 2 conditions has been challenged in recent years.

A 2014 systematic review found that although the majority of studies reported an association between these 2 conditions, many did not include a control group, were of poor methodological quality and did not adjust for confounding variables such as age, sex, and anticoagulation1.  Indeed, a larger study that controlled for many potential confounding factors failed to confirm such an association2.  A small prospective study also found no correlation between the severity of hypertension and epistaxis3.

Even when an association between hypertension and epistaxis has been found, it is unclear how much of the stress of bleeding itself and white coat syndrome may affect the readings1. However, an interesting 2017 study found masked hypertension (normal blood pressure in office, abnormal on ambulatory measurements) in 33.3% of patients with epistaxis with night time blood pressures that were significantly higher among patients with epistaxis4.

So the data is all over the place! It makes sense that long standing hypertension through its effects on blood vessels such as atherosclerosis and endothelium dysfunction may set the stage for epistaxis1,5, particularly in our ever-aging population on anticoagulants.  But whether hypertension by itself is enough to cause epistaxis is likely to be debated for years to come.  

 

References

  1. Kikidis D, Tsioufis K, Papanikolaou V, et al. Is epistaxis associated with arterial hypertension? A systematic review of the literature 2014;271:237-243. https://www.ncbi.nlm.nih.gov/pubmed/23539411
  2. Fuchs FD, Moreira LB, Pires CP, et al. Absence of association between hypertension and epistaxis: a population-based study. Blood Press 12:145-48. http://www.tandfonline.com/doi/abs/10.1080/08037050310001750
  3. Knopfholz J, Lima-Junior E, Précoma-Neto D, et al. Association between epistaxis and hypertension: A one year follow-up after an index episode of nose bleeding in hypertensive patients. Internat J Cardiol 2009;134:e107-e109. https://www.ncbi.nlm.nih.gov/pubmed/18499285
  4. Acar B, Yavuz B, Yildiz E, et al. A possible cause of epistaxis: increased masked hypertension prevalence in patients with epistaxis. Braz J Otorhinolaryngol 2017;83:45-49. http://www.scielo.br/pdf/bjorl/v83n1/1808-8694-bjorl-83-01-0045.pdf
  5. Celik T, Iyisoy A, Yuksel UC, et al. A new evidence of end-organ damage in the patients with arterial hypertension: epistaxis? Internat J Cardiol 2008;141:105-107. https://www.ncbi.nlm.nih.gov/pubmed/19138805
Does hypertension cause epistaxis?

Can I assess the severity of aortic stenosis by physical exam alone?

Even in this age of high-tech medicine, physical exam is still a great starting point for assessing the severity of aortic stenosis (AS) even if you are not a skilled cardiologist like most.

Start out by listening over the right clavicle. If you don’t hear a systolic murmur, you can be pretty confident that your patient doesn’t have moderate to severe AS (>98% sensitivity, LR 0.10)1.

If you hear a systolic murmur look for combination of findings that may increase the likelihood of moderate to severe AS: slow carotid artery upstroke, reduced carotid artery volume, maximal murmur intensity at the second right intercostal space, and reduced intensity of the second heart sound.  The presence of 3 or 4 of these signs increases the likelihood of moderate to severe AS (LR 40), with less than 3 not helping much1.

When considered individually, many of the signs we often attribute to significant AS2 may not be as helpful in part because most of us are not skilled cardiologists and over the years the cause of AS has changed from primarily rheumatic heart disease-related to that advancing age and valve degeneration3.  

So it may not be surprising that murmur intensity (eg grade 3/6 or above) may have a poor sensitivity and is an unreliable predictor of the severity of AS when patients with left ventricular failure are also studied3.  Remember also that the absence of the 2nd sound may not distinguish between moderate and severe AS4

 

References

  1. Etchells E, Glenns V, Shadowitz S, et al. A bedside clinical prediction rule for detecting moderate or severe aortic stenosis. J Gen Intern Med 1998;13:699-704. https://link.springer.com/article/10.1046/j.1525-1497.1998.00207.x
  2. Etchells EE, Bell C. Robb KV. Does this patient have an abnormal systolic murmur? JAMA 1997;277:564-71. https://www.ncbi.nlm.nih.gov/pubmed/10376577
  3. Das P, Pocock C, Chambers J. The patient with a systolic murmur: severe aortic stenosis may be missed during cardiovascular examination. Q J Med 2000;93:685-8. https://oup.silverchair-cdn.com/oup/backfile/Content_public/Journal/qjmed/93/10/10.1093_qjmed_93.10.685/1/930685.pdf?Expires=1500852139&Signature=TwyO6Z4fUfbPc1yiA~2xZC7jOjed0juH604DshdvRYy~VqeNQ57Sv1yE-LNsImthgQogkawMruBPdXn6PvVCVmdvXxE9QsMzQYhZ13JqXDTQhRiPBcsIBKDdROr~xbz0gp0nv-zEmjCp1M8-CXjrlVnjVtwJ6q2nIPTRW5h-CUOnDAmf8vCeJHRi2M9Dt3a4vGALDJQPaETvxKDfoADamBDtZHzzoCIH3OyXT3–jHRtv9AJI2uHlzN79Vzkh~oIrR-rI5mkHle3Yz0R3qIBY0l4P3PssMng~v-IXMNKS~Ghjav8YFTigHN23aEA5yUYllsC7hR25L6h9PA0SZP3QA__&Key-Pair-Id=APKAIUCZBIA4LVPAVW3Q
  4. Aronow WS, Kronzon I. Prevalence and severity of valvular aortic stenosis determined by Doppler echocardiography and its association with echocardiographic and electrocardiographic left  ventricular hypertrophy and physical signs of aortic stenosis in elderly patients. Am J Cardiol 1991;67:776-7. https://www.ncbi.nlm.nih.gov/pubmed/1826070
Can I assess the severity of aortic stenosis by physical exam alone?