Krazy Glue

Krazy Glue you might ask? We'll get there with a case...

A female in her late 70s presents to you with chest pain and is found to have critical aortic stenosis (valve area 0.8 sq-cm). In addition, she has sustained an acute lateral wall MI, but has an ejection fraction of 60% on echo. Angiography confirms AS and demonstrates complete occlusion of the left circumflex artery with no identifiable targets. She is admitted to the CICU and scheduled for aortic valve replacement after the weekend.

How does symptomatic aortic stenosis typically present?

1. Angina pectoris (66%, only half having coronary artery disease)
2. Syncope (25%)
3. Heart Failure

When does aortic stenosis become symptomatic?

Typically, when the aortic valve area is less than 1 sq-cm.

What is the pathophysiology of angina pectoris associated with aortic stenosis?

1. left ventricular hypertrophy places demand on coronary blood supply
2. increased systolic ejection pressures and LVEDP increase myocardial work and oxygen demand
3. prolongation of the systolic ejection time decreases time for diastolic coronary blood flow

Well, in the wee hours of Saturday morning, you are notified that she has acutely decompensated and take her for emergent valve repair. You perform a median sternotomy and are surprised to find upon opening the pericardial sac the presence of a bloody effusion that had been likely causing tamponade. Her hypotension begins to resolve and you place her on cardiopulmonary bypass. You then proceed to manipulate and remove the large amounts of clot, but while filling the heart you cannot locate an obvious site of left ventricular wall rupture... however, the lateral wall has a bruised region from infarct that seems a likely culprit.

What is Beck's Triad?

Classic signs of cardiac tamponade:
1. Elevated venous pressures
2. Systemic arterial hypotension
3. Muffled heart sounds

What are mechanical complications of myocardial infarction?

1. Free rupture of the left ventricular wall
2. Left ventricular aneurysm
3. Ventricular septal defect

Who first described free rupture of the left ventricular wall?

William Harvey in 1647

Harvey also described the nature of blood circulation, hypothesizing that it travelled in a circuit, pumped by the heart (contradicting Galenic theories that blood was constantly absorbed by the body and produced by the liver).

What are methods to repair free rupture of the left ventricular wall?

1. Infarctectomy and buttressed repair with felt strips
2. Placement of a patch with glue

So, you ask for the Krazy glue, hiding a smile behind your mask as you imagine the flailing construction worker suspended by the wiles of his hat. Sure enough, tubes of sterilized store-bought cyanoacrylate appear before you floating in a basin (even with the cute little green push pins). You cut a circular patch of bovine pericardium and adeptly apply the adhesive... then slap it down on the lateral wall. You change gloves and the case then proceeds uneventfully with replacement of the aortic valve.

When were cyanoacrylates given US FDA approval?

In 1998, the FDA gave Closure Medical Corporation (Raleigh, NC) approval to market 2-octyl cyanoacrylate for closing wounds and surgical incisions. In 2002, they were also approved for marketing it as an adhesive that acts as a barrier against microbial penetration. In 2000, n-butyl cyanoacrylate was approved for use as an liquid embolic agent for cerebral AVMs.

What are trade names of marketed medical cyanoacrylates?

Dermabond (Ethicon/J&J) - surgical wound closure
Orabase Soothe-n-Seal (Colgate/Palmolive) - Canker sores
Liquid Bandage (Band Aid/J&J) - Cracked skin, shaving nicks
Nexaband (Abbott) - veterinary wound closure
Trufill (Cordis/J&J) - embolic system for cerebral AVMs

Histoacryl (Braun, Germany), a n-butylcyanoacrylate, has been used worldwide (but not in the US) for some time as a tissue adhesive.

What is the difference between n-butyl and 2-octyl cyanoacrylates?

n-butyl has lower tensile strength and is more brittle

How is Dermabond packaged?

In sterile 0.5ml plastic-encased glass-ampule applicators, or 0.5ml and 0.75ml pen applicators.

How do you apply Dermabond?

1. Make sure the wound is clean with adequate hemostasis.
2. Relieve tension in the wound as necessary with deep dermal suture placement.
3. Crush applicator's glass vial and allow applicator to express adhesive.
4. Approximate wound edges manually or with forceps.
5. Brush thin layer of adhesive on wound without allowing it to enter wound.
6. Allow to polymerize for 30-45 seconds.
7. Add 2 more layers of adhesive, waiting 5-10 seconds between applications.

How do cyanoacrylates work?

Through a polymerization reaction that is catalyzed by the presence of water. The presence of moisture on a surface or in the air will accelerate the process.

What is the role of cyanoacrylates in heart surgery?

Experience using Methyl-2-cyanoacrylate in clinical cardiac surgery was described by Nina S. Braunwald in 1966, who reported its use favorably as a hemostatic agent on the heart and aorta in 24 patients. At the time methyl-2-cyanoacrylate was called Eastman 910 monomer; presently it is marketed as Krazy Glue or Superglue.

Since then, there have been sporadic case reports of sutureless repair of cardiac rupture using glue and patch technique with cyanoacrylates. More recently, Lachapelle et al. reported the results of 6 patients with left ventricular free wall rupture who were managed using an elliptical Teflon felt patch and Histoacryl adhesive, all who acheived hemostasis, with one postoperative mortality related to a stroke.

Who was Nina S. Braunwald?

Nina Starr Braunwald, MD (1928-1992) was the first female to perform open heart surgery. In 1960, she led the operative team that implanted the first artificial mitral valve (the first successful human heart valve replacement), which she created herself out of polyurethane and Teflon. Later, she developed the Braunwald-Cutter valve, a cloth-covered mechanical prosthesis, as well as a stented aortic homograft for mitral valve replacement. She also managed to have a family with three children.

Late... SG

Sources:
Norton's Surgery: Basic Science and Clinical Evidence (2001).
Braunwald E. Nina Starr Braunwald: Some Reflections on the First Woman Heart Surgeon. Ann Thorac Surg 2001; 71: S6-7.
Braunwald NS. A Clinical Evaluation of Methyl-2-cyanoacrylate Monomer as a Hemostatic Agent on the Aorta. Ann Surg 1966; 164(6): 967-972.
Lachapelle K, deVarennes B, Ergina PL, Cecere R. Sutureless Patch Technique for Postinfarction Left Ventricular Rupture. Ann Thorac Surg 2002; 74: 96-101.
Singer AJ, Thode HC. A review of the literature on octylcyanoacrylate tissue adhesive. Am J Surg 2004; 187: 238-248.
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