Day by day, she was losing her breath more and more quickly. Compared to the previous day, she noticed little change, but when she thought back a week or so, the steady worsening was unmistakable.

"I'd washed my hair on a Saturday evening, and it absolutely exhausted me," Albright said. "It just wasn't how I'd lived the previous 75 years–without the strength to pick up a hairdryer."

Albright, now 77, called her daughter and said she needed to go to the emergency room the following morning. Wisely, her daughter noted that an emergency is not something that can wait until the next day. The Toluca Lake resident, a former Los Angeles Unified School District principal who now coaches new principals, accepted her daughter's help and good advice, and headed to Cedars-Sinai around midnight.

Doctors in the Emergency Department discovered a blood clot that had traveled to Albright's lungs, a condition known as a pulmonary embolism.

For nearly a quarter of pulmonary embolism patients, the first sign of their condition is death. In Albright's case, her condition began as a clot in her leg, known as deep vein thrombosis, or DVT . Part of the clot broke away and traveled to her lung.

Read: Pulmonary Hypertension: A Patient’s Advice

DVT often goes undetected, because symptoms, such as pain or swelling in the leg, shortness of breath, chest pain, coughing and dizziness, are missed or dismissed as minor. And in some cases, there are no symptoms until it is too late.

"Most of the time, patients aren't diagnosed until it's too late," said Victor Tapson, MD, director of clinical research at the Women's Guild Lung Institute. "People go to their doctors with shortness of breath, and they might be told they have asthma or they're out of shape. Someone might think they have a charley horse in the leg, and deep vein thrombosis might not even register as a possible diagnosis.

"Pulmonary embolism is kind of a masquerader. Clinicians have to think about the disease and the risk factors."

Techniques for treating the condition continue to advance. For many patients, blood thinners are the treatment of choice. There are other options when clots are especially large, like Albright's was.

In her case, Tapson recruited cardiologist Hooman Madyoon, MD to use a catheter-based procedure that uses ultrasound energy and delivers low doses of clot-busting drugs directly to the lung, to break up the clot.

Then a filter was placed in a vein in her abdomen to catch any future clots that might break off, stopping them from getting to her lungs.

Albright met Tapson after she was admitted to the intensive care unit. He examined her chart, listened carefully to her when she answered his questions, and then they settled on a course of action. He updated her daughters by text message and met with them after the treatment.

"We were really impressed," she said. "We've never had that kind of care. He was so supportive of my daughters and their questions."

Tapson has authored and co-authored more than 220 articles in peer-reviewed journals on his research on pulmonary vascular disease, including pulmonary embolism, deep vein thrombosis and pulmonary hypertension, and is considered a leading expert in the field.

His early research in the area of venous thromboembolism included laboratory studies and clinical trials of drugs to treat massive pulmonary embolism. He also studied the use of MRI in diagnosing DVT, and served as a principal investigator of national and international registries of DVT patients to study and prevent the disease. Tapson has also led a 4,000-patient study to determine benchmarks for anticoagulation, as well as trials evaluating drug treatments for the condition.

"Dr. Tapson is right at the leading edge of what's going on with this research," Albright said. "Being connected with someone who has been with the research, seen the growth, and knows what works is very comforting."

Albright offers the following advice to patients who notice they're having trouble catching their breath:

Read: Pulmonary Embolism Team Among First in the Nation

If she'd known then what she knows now, she would have made an appointment with her doctor or gone to the emergency room sooner, and not waited until she was struggling to breathe.

If you sense something is unusual, monitor it very closely. If the condition worsens, act immediately.

Read: Shortness of Breath: When to See Your Doctor

Albright will continue taking medication to manage her DVT for the rest of her life. She recommends applying the same method she coaches her new principals to adopt: "Routinization."

"I tell them when they're getting ready for bed at night, and you're brushing your teeth, look at that person in the mirror and say, ‘What have I done for myself today?'" she said. "Make sure you have an answer for that."

Her own routine is to keep her pill sorter on her breakfast table. When she finishes her morning cup of coffee, she puts the pill sorter on top of it. This reminds her to take her medication on a regular, habitual basis. "Simple and regular" are her watchwords.

In addition to having a routine to make sure medications are taken on time, Albright suggests ditching your watch. She stopped wearing hers 25 years ago, when she realized that when she looked at it, she wasn't thinking about what she should be doing in the moment, but how little time she had until the next thing she needed to do.

"I don't need to know exactly what time it is, and there are clocks all over the place," she said. "Just eliminate as much needless stress as possible."