Examiner.com posted “Lung Surgery after cardiac stents: When and How” by Kristin Eckland.
This is the first in a two-part discussion on lung surgery after cardiac stent placement.
Modern medicine has become a myriad of published recommendations and guidelines for the standardization of treatment. These guidelines are based on years of research, clinical trials and meta-analyses by many of the world’s leading experts in medicine.
Treatment guidelines to standardize care
Nowhere is this more apparent than in the field of cardiology, which encompasses the treatment of acute illnesses such as a heart attack as well as more chronic conditions such as hypertension, atrial fibrillation and heart failure. Included in this long list of treatment guidelines are recommendations for patients undergoing surgery.
Guidelines for patients undergoing surgery
These guidelines recommend who should undergo additional cardiac testing prior to surgery, and how long to wait after cardiac procedures (like stent placement*) before elective surgery. There are guidelines on when to start, and when to stop anti-coagulation and anti-platelet medications before and after surgery. In fact, many people don’t know that one of these guidelines recommends that patients with cardiac conditions continue their aspirin prior to surgery, whether it’s hip replacement, breast augmentation or even open-heart surgery. Most people, doctors included, used to worry about bleeding caused by aspirin in surgery but we now know that stopping aspirin in these patients is actually more dangerous. So these guidelines are helpful for keep doctors in other fields up to date with the latest scientific data.
Guidelines post-PCI
Current guidelines after cardiac stents recommend delaying elective or non-urgent surgery for up to a year after stent placement . This delay is related to the use of strong anti-platelet medications such as prasugrel (Effient) and clopidogrel (Plavix). These “super-aspirin” drugs inhibit the normal clot formation activities of platelets, which is critical to prevent stent thrombosis (a life-threatening emergency) while the blood vessels heal from having the stent implanted. While preventing the blood from clotting is important during this phase of recovery, it also makes the potential for bleeding after surgery or injury a near certainty.
But I need surgery
But sometimes patients need operations, particularly cardiac operations before this time period is up. In that case, depending on the absolute urgency, doctors have a couple of options; 1. Stop the drugs and ‘bridge’ the patient with more short acting medications like enoxaparin or heparin while waiting for the original drugs to wear off or, in more urgent or emergent cases: 2. take the patient directly to surgery; hope for the best and administer multiple blood products. It’s not as simple as it sounds, the residual drug (such as clopidogrel) in the patient’s body will bind with the transfused platelets and inactivate them, rending the new platelets as ineffective as the old ones. The other concern with this approach is that giving patients blood transfusions during surgery increases their risk of having multiple complications. But, in an emergency with a critically ill patient, it may be the only option.
The semi-urgent patient: Ms. X
However, despite this wealth of information available, there is no clear-cut consensus on how to manage a third category of patient; the semi-urgent patient. These are patients who have received cardiac stents in the past six months, and present with a serious but nonemergent medical problem. Due to the overwhelming success of cardiac angioplasty and stent procedures, this class of patient is growing. A classic example would sound something like this:
Ms. X** is a 66 year old Caucasian female with a long history of heavy smoking, hypertension and high cholesterol. She is otherwise active and healthy. One month ago, while working in her garden, she became pale, and clammy and complained of being very nauseated with heartburn-like symptoms. Luckily for Ms. X, her family recognized that she was having a medical emergency and took her directly to the emergency room of the nearest hospital.
After arriving at the hospital, she was immediately evaluated and treated. Doctors and nurses administered aspirin, nitroglycerin, morphine and oxygen while performing an EKG and drawing cardiac enzymes. Within 20 minutes of her arrival, the cardiologist reviewed her history and EKG and determined that Ms. X was having a heart attack. She was immediately prepped and taken to the cardiac catheterization lab, where a drug-eluting stent was placed to the left anterior descending coronary artery to restore blood flow to her heart.
After the procedure she was transferred to the cardiac care unit where she remained until her discharge 2 days later. Prior to her discharge, she underwent additional testing including a lipid panel, platelet mapping, hemoglobin A1C and a chest x-ray. She was also placed on a new medication regimen which included a baby aspirin, clopidogrel, carvedilol and pravastatin.
At her follow-up appointment one week later, Ms. X reported that she was feeling well and back to her routine activities. However, the cardiologist informed her that the chest x-ray from the hospital was abnormal, and referred her to a thoracic surgeon for a 2 cm spiculated nodule in the periphery of the lower lobe of her right lung.
After seeing the thoracic surgeon and undergoing additional tests, it appears that Ms. X has an early stage lung cancer that could potentially be cured with surgery. However, Ms. X and her physicians are trying to determine when to perform her surgery. Waiting 12 months, as recommended for elective or non-urgent surgery, until Ms. X completes her clopidogrel regimen for her stent means that her cancer may have time to grow and spread. But if Ms. X has surgery immediately, she is at increased risk of serious complications such as having another heart attack during surgery or severe bleeding.
While Savonetti, Caracciolo, Callaneo & De Servi published recommendations based on their meta-analysis in 2009, the majority of the patients involved were undergoing cardiac or vascular surgery. Similarly, two teams of Italian researchers led by Dr. Roberta Rossini and Dr. Matteo DiMinno investigated the issue but came to very different conclusions. But until recently, few researchers had looked specifically at patients undergoing lung surgery. This is important because lung surgery itself carries its own risks and complications.
These complications are compounded in patients with significant co-morbid conditions such as cardiac disease, but there is little published data to clearly outline this risk to patients.
* Cardiac stent placement is also known as percutaneous coronary intervention or PCI. Duration of anti-platelet therapy is based on patient characteristics, additional risk factors and stent type.
**Ms. X is based on patient composites, not a specific individual.
This is the first of a two-part discussion on lung surgery after stents. In the next article, we will review the data surrounding lung surgery after stent placement.