1. Disease and Description: The human body uses the cardiovascular system as a physiological highway to deliver oxygen, hormones, nutrients, and a variety of other integral substances to cells and tissues. Cellular waste also employs the cardiovascular system as a transport mechanism for eventual removal from the body. The cardiovascular system is made up of the heart and blood vessels Nelms, (Marcia 2004).
Functionally, the heart is the engine that pumps blood through the vasculature dropping off nutrients and oxygen to cells along the way. The heart is made up of four chambers: the right atrium, right ventricle, left atrium, and left ventricle (McArdle, et al., 2007). Oxygenated blood is pumped from the heart through systemic circulation in arteries to capillaries. The capillaries are where exchange of oxygen, cellular substrates, and by- products occurs. After deoxygenated blood exits capillary beds it begins its journey back to the heart through the network of veins eventually leading to the vena cava which enters the heart at the right atrium. From the right atrium blood passes through the tricuspid valve and enters the right ventricle. This deoxygenated blood is pumped through pulmonary circulation to the lungs where the blood drops off carbon dioxide and is re-oxygenated. The re-oxygenated blood is sent back to the heart and enters via the left atrium. The left atrium delivers blood to the left ventricle through the mitral valve. The left ventricle exits the heart through the aortic valve and sends the oxygenated blood through systemic circulation (McArdle, et al., 2007).
The valves between the chambers and exiting each ventricle help maintain pressure. Pressure is essential to propel blood throughout the body. Diastolic blood pressure, or the amount of pressure keeping the aortic valve closed, must be overcome by the heart to deliver blood systemically. The pressure that overcomes diastolic blood pressure is known as systolic blood pressure. Systole is when the heart is contracted and diastole is when the heart is at rest (Corwin. E. J., 2000). Essentially, pressure and valves keep blood coursing forward through circulation.
In the case of aortic regurgitation the aortic valve allows retrograde blood flow back into the left ventricle during diastole, the period after contraction of the ventricles (Bekeredjian & Grayburn, 2005). The three dysfunctional classes with aortic regurgitation are 1) aortic dilation, 2) cusp prolapsed, and 3) restrictive malfunctions (Boodhwani, et al., 2009). Any of these dysfunctional classes cause the aortic valve, which is composed of three leaflets, to not close securely therefore allowing leakage or regurgitation back into the left ventricle. Since normally blood flows in one direction and is restricted from backflow by pressure and normal functioning valves, this is a malfunction. The failure in normal function decreases the pressure that propels the blood which overcomes diastolic pressure to move through the body. This leakage may prevent the heart from efficiently pumping blood to the rest of the body. As a result cells in need of oxygen and metabolic substrates may have to “wait” for these to be delivered. In an attempt to compensate for the loss in pumping efficiency and due to the extra blood remaining in the left ventricle the heart may over work and hypertrophy. Left ventricular hypertrophy (LVH) can lead to a host of issues that further decrease the efficiency of the heart’s pump (Soojeong, et al., 2009). Eventually congestive heart failure may result from LVH (Corwin. E. J., 2000).
2. Risk Factors/causes: The causes for aortic regurgitation are many and include 1) congenital factors including being born with just one or two leaflets for the aortic valve. 2) The aortic valve may not close completely allowing back flow. 3) General wear and tear related to age may also contribute to the development as well as 4) damage as a result of endocarditis, or inflammation of the interior lining of the heart. 5) Rheumatic fever has been shown to damage not only the aortic valve but other heart valves as well. 6) Trauma that damages part of the aorta, 7) Mafan’s syndrome, and 8) hypertension all can result in aortic regurgitation (Mayo, 2007). In the case of hypertension, excess diastolic pressure pushes against the aortic valve, over time this may compromise the valves integrity eventually resulting in leakage (Bekeredjian & Grayburn, 2005).
Whatever the cause may be, aortic regurgitation results in abnormal blood flow through the heart and vessels. This abnormal flow puts one at an increased risk for developing more advanced aortic regurgitation later in life.
Acute aortic regurgitation is a surgical emergency and results in severe pulmonary edema and hypotension. Chronic severe aortic regurgitation causes left ventricular pressure and volume overload resulting in systolic hypertension (Bekeredjian & Grayburn, 2005).
3. Diagnosis: A doctor can detect aortic regurgitation with a stethoscope or other medical tests such as: echocardiograms, chest x-rays, electrocardiograms (ECG), cardiac catheterization, exercise tests, and transesophageal echocardiograms. Doppler Ultrasound is also an effective tool to see valve heart defects (Duplex, 2009). Each of these diagnostic tests creates a picture of the heart or its activity and provides information about normal and abnormal functions. By comparing the data these tests provide with normal data allows one to see issues with the aortic valve. An echocardiogram is generally the preferred test used to diagnose and monitor the progression, assess severity, and examine the effects on the left ventricle (Bekeredjian & Grayburn, 2005).
Aortic regurgitation may be present without the patient knowing it. In mild cases the heart will compensate but as the disorder progresses it can present with signs and symptoms (Bekeredjian & Grayburn, 2005) that include: fainting, irregular heart rhythm, edema in the extremities, chest pain, shortness of breath - especially during exercise, tiredness, and heart palpitations. These may be reasons for one to visit the doctor where diagnosis can occur.
Aortic regurgitation may not pose any serious health threats if it is mild, however, severe cases may result in congestive heart failure. Congestive heart failure is a condition in which the heart is unable to pump enough blood to meet your body’s needs (Nelms, Marcia 2004).
4. ECG Presence: There is no ECG readout that specifically indicates aortic regurgitation. Aortic regurgitation can show itself on an ECG as LVH since LVH is often a result of advanced aortic regurgitation. There may be, however, no observable abnormalities on an ECG with mild cases. One can see an example of LVH resulting from aortic regurgitation from Figure 1. In Figure 1 LVH is indicated by the voltage of the R wave for V5 lead.
Figure 1. Picture did not translate to blogger.com. I can be view @:
(www.focusonfabry.com/healthcare_cardiac.aspx)
5. Treatment: The most effective treatment for aortic regurgitation is surgery. Decreased heart function and excessive regurgitation are the two factors considered when surgery is indicated (MayoClinic.com, 2007). Valve surgery should be administered before the left ventricular ejection fraction falls below 55% or the left ventricular end diastolic dimension reaches 55mm (Bekeredjian & Grayburn ,2005). Treatment depends upon the severity and the signs and symptoms one presents with, and whether the heart function is compromised. By the time that signs and symptoms are present surgery is generally needed and recommended. It is important to track the progression of valvular deterioration. This allows the correct treatment to be given at the correct time. Even without signs and symptoms, if the heart is weakening one will likely need surgery. By forgoing surgery early on it may cause the heart to become weakened beyond repair (MayoClinic.com, 2007).
Two surgical treatments for aortic regurgitation are valve repair and valve replacement.
Valve repair surgery is done to repair the function of the faulty valve and eliminate regurgitation. Valve replacement surgery utilizes a prosthetic valve to correct regurgitation. This surgery would be necessary if the aortic valve is beyond repair. There are two types of valve replacement surgery – mechanical and tissue (MayoClinic.com, 2007).
Mechanical surgery involves metal valves. Mechanical replacement procedures carry the risk of clots forming at or near the replacement valve site. Long term anticoagulants are required with mechanical valve replacements (MayoClinic.com, 2007).
Tissue valve replacements come from cow, pig, or human cadavers. These are not as durable and can wear out which may require future surgery. Tissue valve replacements, however, do not require long term anticoagulant therapy. Autografts are also possible. This procedure uses one’s own pulmonary valve to replace the faulty aortic valve. Surgery usually corrects aortic regurgitation and normal activities can be resumed shortly after the procedure (MayoClinic.com, 2007).
There are no pharmaceutical therapies to cure aortic regurgitation. Vasodilators and/or antibiotics may be used to reduce symptoms and delay the need for surgery. In the case that surgery is not an option vasodilators may also be used (Bekeredjian & Grayburn, 2005). Vasodilators are used to open up blood vessels peripherally. This reduces the diastolic blood pressure that must be overcome by the left ventricle (Corwin. Elizabeth, J. 2000). Antibiotics can help to reduce infection of the interior lining of the heart. Anticoagulants are used in the case of mechanical valve replacement to prevent clotting (Bekeredjian & Grayburn, 2005).
Preventative steps to avoid aortic regurgitation include reducing hypertension, avoiding blood infections and activities that lead to blood infections, and preventing the development of rheumatic fever. Exercise is an important way to reduce blood pressure and may help reduce the risk of developing aortic regurgitation (MayoClinic.com, 2007). Future therapies may focus on molecular mechanisms to delay left ventricular fibrosis (Bekeredjian & Graybrurn, 2005).
6. Provide a research paper using people with this condition and a treatment:
J Thorac Cardiovasc Surg 2009;137:286-294
© 2009 The American Association for Thoracic Surgery
| Acquired Cardiovascular Disease |
Repair-oriented classification of aortic insufficiency: Impact on surgical techniques and clinical outcomes
Munir Boodhwani, MD, MMSc, Laurent de Kerchove, MD, David Glineur, MD, Alain Poncelet, MD, Jean Rubay, MD, Parla Astarci, MD, Robert Verhelst, MD, Philippe Noirhomme, MD, Gébrine El Khoury, MD*
Department of Cardiovascular and Thoracic Surgery, Cliniques Universitaires Saint-Luc, Brussels, Belgium
Received for publication May 5, 2008; revisions received July 30, 2008; accepted for publication August 31, 2008.
* Address for reprints: Gébrine El Khoury, MD, Service de Chirurgie Cardiovasculaire et Thoracique, Cliniques Universitaires Saint-Luc UCL 90, Ave Hippocrate 10, Brussels B-1200, Belgium. (Email: elkhoury@chir.ucl.ac.be).
Objective: Valve repair for aortic insufficiency requires a tailored surgical approach determined by the leaflet and aortic disease. Over the past decade, we have developed a functional classification of AI, which guides repair strategy and can predict outcome. In this study, we analyze our experience with a systematic approach to aortic valve repair.
Methods: From 1996 to 2007, 264 patients underwent elective aortic valve repair for aortic insufficiency (mean age – 54 ± 16 years; 79% male). AV was tricuspid in 171 patients bicuspid in 90 and quadricuspid in 3. One hundred fifty three patients had type I dysfunction (aortic dilatation), 134 had type II (cusp prolapse), and 40 had type III (restrictive). Thirty six percent (96/264) of the patients had more than one identified mechanism.
Results: In-hospital mortality was 1.1% (3/264). Six patients experienced early repair failure; 3 underwent re-repair. Functional classification predicted the necessary repair techniques in 82-100% of patients, with adjunctive techniques being employed in up to 35% of patients. Mid-term follow up (median [interquartile range]: 47 [29–73] months) revealed a late mortality rate of 4.2% (11/261, 10 cardiac). Five year overall survival was 95 ± 3%. Ten patients underwent aortic valve reoperation (1 re-repair). Freedoms from recurrent Al (>2+) and from AV reoperation at 5 years was 88 ± 3% and 92 ± 4% respectively and patients with type I (82 ± 9%; 93 ± 5%) or II (95 ± 5%; 94 ± 6%) had better outcomes compared to type III (76 ± 17%; 84 ± 13%).
Conclusion: Aortic valve repair is an acceptable therapeutic option for patients with aortic insufficiency. This functional classification allows a systematic approach to the repair of Al and can help to predict the surgical techniques required as well as the durability of repair. Restrictive cusp motion (type III), due to fibrosis or calcification, is an important predictor for recurrent Al following AV repair.
Abbreviations and Acronyms AI = aortic insufficiency; STJ = sinotubular junction; VAJ = ventriculoaortic junction
J Thorac Cardiovasc Surg 2009;137:286-294
© 2009 The American Association for Thoracic Surgery
(Boodhwani, Munir 2009)
The study looked at 264 patients with aortic regurgitation who chose to have surgical repair to the faulty aortic valve. Up to five years after surgery 95 ± 3% of the participants survived. Re-repair of the aortic valve after 5 years was around 15% across all groups.
The article concludes that repair of a regurgitating/insufficient aortic valve has beneficial outcomes for all classifications of aortic regurgitation.
References
Bekeredjian, R., & Grayburn, P. A. (2005). Valvular heart disease: Aortic regurgitation. Circulation, 112, 125-134.
Boodhwani, M., de Kerchove, L., Glineur, D., Poncelet, A., Rubay, J., Astarci, P., et al. (2009). Repair-oriented classification of aortic insufficiency: Impact on surgical techniques and clinical outcomes .137(2), 286-294.
Corwin. Elizabeth, J. (2000). The cardiovascular system. In H. Surrena, B. Getnzler, T. Gibbons & E. Kors (Eds.), Handbook of pathophysiology (3rd ed., pp. 392-463). Philadelphia: Lippincott, Williams, and Wilkins.
MayoClinic.com. (2007). Aortic valve regurgitation. Retrieved 03/30, 2009, from http://www.mayoclinic.com/health/aortic-valve-regurgitation/DS00419
McArdle, W. D., Katch, F. I., & Katch, V. L. (2007). The cardiovascular system. Exercise physiology energy, nutrition, and human performance (6th ed., pp. 313-332). Philadelphia: Lippincott, Williams, and Wilkins.
Nelms, M., & Anderson, S. L. (2004). Medical nutrition therapy for cardiovascular disorders. In E. Howe, & M. Chang (Eds.), Medical nutrition therapy: A case study approach (2nd ed., pp. 55). Belmont, CA: Wadsworth.
Soojeong, C., Haesun, S., Mooyong, P., Jinkuk, K., & Seungduk, H. (2009). Fabry disease with aortic regurgitation. The Annuls of Thoracic Surgery, 87(2), 625-628.
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